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SOIL SURVEY VIRGIN ISLANDS of the United States _—S as = eo = Bhd: ) i; boy aa — UNITED STATES DEPARTMENT AGRICULTURE Soil Conservation Service Issued August 1970 Major fieldwork for this soil survey in 1965. Conservation District. HOW TO USE THIS THIS SOIL SURVEY contains information that can be applied in managing farms, ranches, and woodlands; in selecting sites for roads, ponds, buildings, or other structures; and in appraising the suitability of tracts of land for farming, industry, or recrea- tion. Locating Soils All the soils of the Virgin Islands are shown on the detailed map at the back of this survey. This map consists of many sheets that are made from aeri- al photographs. Each sheet is numbered to corre- spond with a number shown on the Index to Map Sheets. On each sheet of the detailed map, soil areas are outlined and are identified by symbol. All areas marked with the same symbol are the same kind of soil. The soil symbol is inside the area if there is enough room; otherwise, it is outside and a pointer shows where the symbol belongs. Finding and Using Information The "Guide to Mapping Units" can be used to find information in this publication. This guide lists all of the soils of the islands in alphabetic order by map symbol. It shows the page where each kind of soil is described and the page for the capability unit and the range site. It also shows the wood- land group in which the soil has been placed. Interpretations not included in this survey can be developed by grouping the soils according to their suitability or limitations for a particular use. Translucent material can be used as an overlay over the soil map and colored to show soils that have the same limitation or suitability. For exam- Soil names and descriptions were approved in 1965. Unless otherwise in- dicated, statements in the publication refer to conditions on the islands This survey was made by the Soil Conservation Service. part of the technical assistance furnished to the Virgin Islands Soil Either enlarged or reduced copies of the soil map in this publication can be made by commercial photographers, or they can be purchased on in- dividual order from the Cartographic Division, Soil Conservation Service, United States Department of Agriculture, was done in the period 1964-65. It is Washington, D. C. 20250. SOIL SURVEY ple, soils that have a slight limitation for a given use can be colored green, those with a moderate lim- itation can be colored yellow, and those with a se- vere limitation can be colored red. Farmers and those who work with them can learn about use and management of the soils from the soil descriptions and from the discussions of the capa- bility units, the woodland groups, and the range sites. Foresters and others can refer to the section "Use of the Soils for Woodland,'' where the soils of the islands are grouped according to their suitabil- ity for trees. Ranchers and others can find under "Use of the Soils for Range" groupings of the soils according tc their suitability for range and descriptions. of the vegetation on each range site. Engineers and builders can find under 'Use of the Soils in Engineering"! tables that describe soil properties that affect engineering and show the rel- ative suitability of the soils for specified engi- neering purposes. Scientists and others can read about how the soils formed and how they are classified in the. sec- tion "Formation and Classification of the Soils." Newcomers on the islands may be especially inter- ested in the section "General Soil Map,' where broac patterns of soils are described. They may also be interested in the section "Additional Facts About the Islands." Cover picture: Coconut palm trees and pangolagrass on sandy coastal soil. For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 CONTENTS Page HOW THIS SURVEY WAS MADE---------------------- 2 GENERAL SOIL MAP------------------------------ 3 1. Descalabrado-Jacana Association-------- 3 2. Aguilita-Fredensborg-Sion Association-- 3 3. Fraternidad-Aguirre-Glynn Association-- 3 4. Southgate-Parasol Association---------- 4 5, Cramer-Isaac Association--------------- 4 6. Dorothea-Victory-Magens Association---- 4 7. Cornhill-Coamo-San Anton Association--- 5 DESCRIPTIONS OF THE SOILS------------- -------- 6 Aguilita Series------++~~--+~- ----+--+-----+ 6 Aguirre Series--------------------- eee’ 8 Coamo Series------------------------------- 9 Cobbly Alluvial Land----------------------- 10 Cornhill Series---------------------------- 10 Cramer Series------------------------------ 11 Descalabrado Series----------------~------- 13 Diamond Series------------------- eeueesesss 14 Dorothea Series---------------------------- 1S Fraternidad Series-------------------------- 16 Fredensborg Series------------------------- 17 Glynn Series------------------------------- 18 Hesselberg Series-------------------------- 19 Isaac Series------------------------------- 20 Jacana Series------------------------------ 21 Jaucas SerieS------------------------------ 22 Lavallee Series---------------------------- 23 Leveled Clayey Land---------------+-------- 24 Leveled Marly Land------------------------- 24 Leveled Rocky Land------------------------- 24 Limestone Rock Land------------------------ 24 Made Land---------------~------------------- 24 Magens Series----------~------------------- 24 Parasol Series----------------------------- 25 Pozo Blanco Series-------~------~----------- 26 San Anton Series----------------------+---- 27 Sion Series-------------------------------- 28 Southgate Series--------------------------- 29 Tidal Flats--------------------------+--+---- 30 Tidal Swamps----------------------------+-- 30 Victory Series----------------------------- 30 Volcanic Rock Land------------------------- 31 Page USE OF THE SOILS FOR CROPS AND PASTURE-------- 32 Capability Grouping------------------------ 32 Estimated Yields--------------------------- 37 USE OF THE SOILS FOR SHADE AND: FRUIT TREES, SHRUBS, AND ORNAMENTALS---~--~------------ 39 USE OF THE SOILS, FOR RANGE-----~---------------- 39 Range Sites and Condition Classes---------- 39 Descriptions of Range Sites---------------- 39 USE OF THE SOILS FOR WOODLAND----------------- 45 Woodland Suitability Groups---------------- 45 USE OF THE SOILS IN ENGINEERING--------------- 47 Engineering Classifications---------------- 47 Estimated Properties of the Soils---------- 47 Interpretations of Engineering Properties-- 47 Engineering Test Data for Soils------------ 61 USE OF THE SOILS FOR RECREATIONAL DEVELOPMENT- 64 FORMATION AND CLASSIFICATION OF THE SOILS------ 69 Factors of Soil Formation------------------ 69 Plants and Animals----~-~---------------- 69 Climate--------------------------------- 69 Parent Material------------------------- 70 Relief--------~-------------------------- 70 Age of Landform------------------------- 70 Representative Soil Horizons--------------- 70 Classification of the Soils---------------- 71 ADDITIONAL FACTS ABOUT THE ISLANDS------------ 73 Climate--------------------~--------+-+----- 73 Water Supply------------------------------- 75 Natural Vegetation------------------------- 75 LITERATURE CITED-=-2---5-42-45-4--<05-5-2s5 2-2 76 GLOSSARY -~--------------------------- eae eet 77 GUIDE TO MAPPING UNITS--------------- Following 78 SOIL SURVEY OF THE VIRGIN ISLANDS OF THE UNITED STATES BY LUIS H. RIVERA, WAYNE D. FREDERICK, CORNELIUS FARRIS, EARL H. JENSEN, LYLE DAVIS, CECIL D. PALMER, LYLE F. JACKSON, AND WILLIAM E. McKINZIE UNITED STATES DEPARTMENT OF AGRICULTURE, SOIL CONSERVATION SERVICE THE VIRGIN ISLANDS OF THE UNITED STATES consist of St. Croix, St. Thomas, St. John, and about 50 smaller islands that range in size from a cluster of small rocks to a square mile. St. Croix, the largest island and the most east- erly possession of the United States, is approxi- mately 100 miles south-southeast of San Juan, Puerto Rico. It is a little more than 22 miles long, from east to west. The western half is rec- tangular in shape and is about 6 miles wide. The eastern half is about 5 miles wide at Christiansted and tapers to a point at the east end. The area is approximately 54,400 acres, or 85 square miles. St. Thomas, the second largest island, is about 40 miles north of St. Croix and 40 miles east of Puerto Rico. It is about 12 miles long and 3 miles wide, The area is approximately 19,000 acres, or 30 square miles. St. John is about 2 miles east of St. Thomas, just across Pillsbury Sound. It is about 7 miles long and 3 miles wide. The area is approximately 12,000 acres, or 19 square miles. The island of St. Croix is characterized by a mountainous area in the north flanked by a rolling plain to the south. The mountains are broken by many narrow, steep-sided valleys through which in- termittent streams discharge in southerly and southeasterly courses across the plain. Few deeply cut streams flow directly westward. Mount Eagle, the highest peak on St. Croix, is 1,165 feet above sea level. The eastern end of the island is moun- tainous also, but the elevation is not so high and the stream valleys are not so sharply incised. St. Thomas and St. John are characterized by ir- regular coastlines, numerous bays, steep slopes, and small drainage areas. For the most part, the topog- raphy is mountainous. Coastal plains are almost completely absent. There are no permanent streams or rivers. Intermittent streams discharge into the sea, but on their way form narrow, nearly level al- luvial fans and terraces. Crown Mountain, the high- est peak on St. Thomas, is 1,500 feet above sea level. Bordeaux Mountain, the highest peak on St. John, is 1,277 feet above sea level. HOW THIS SURVEY WAS MADE Soil scientists made this survey to learn what kinds of soils are on the Virgin Islands, where they are located, and how they can be used. They went onto the islands knowing they likely would find many soils they had already seen and perhaps some they had not, As they traveled over the islands, they observed steepness, length, and shape of slopes; size and speed of streams; kinds of native plants or crops; kinds of rock; and many facts about the soils. They dug many holes to expose soil profiles. A profile is the sequence of natural layers, or ho- rizons, in a soil; it extends. from the surface down into the parent material that has not been changed much by leaching or by roots. The soil scientists made comparisons among the profiles they studied, and they compared these pro- files with those in areas nearby and in places more distant. They classified and named the soils ac- cording to nationwide, uniform procedures. To use this publication efficiently, it is necessary to know the kinds of groupings most used in a local soil classification. Soils that have profiles almost alike make up a soil series. Except for different texture in the surface layer, the major horizons of all the soils of one series are similar in thickness, arrangement, and other important characteristics. Each soil se- ries is named for a town, an estate, or other geo- graphic feature near the place where a soil of that series was first observed and mapped. Cramer and Magens, for example, are the names of two soil se- ries. All the soils on the islands having the same series name are essentially alike in those charac- teristics that affect their behavior in the natural, undisturbed landscape. Soils of one series can dif- fer somewhat in the texture of the surface layer and in slope, stoniness, or some other characteristic that affects use of the soils by man. Many soil series contain soils that differ in the texture of their surface layer. According to such differences in texture, separations called soil types are made. Within a series, all the soils hav- ing a surface layer of the same texture belong to one soil type. Cramer gravelly clay loam and Cramer stony clay loam are two soil types in the Cramer series. The difference in the texture of their sur- face layers is apparent from their names. Some types vary so much in slope, degree of ero- sion, number and size of stones, or some other fea- ture that affects their use, that practical sugges- tions about their management could not be made if they were shown on the soil map as one unit. Such soil types are divided into soil phases (5).— The name of a soil phase indicates a feature that af- fects management. For example, Cramer gravelly clay loam, 12 to 40 percent slopes, is one of three phases of Cramer gravelly clay loam, a soil type that has a slope range of 5 to 60 percent. 1Underscored numbers in parentheses refer to Literature Cited, page 76. After a guide for classifying and naming the soils had been worked out, the soil scientists drew the boundaries of the individual soils on aerial photographs. These photographs show woodlands, buildings, field borders, trees, and other details that help in drawing boundaries accurately. The soil map at the back of this survey was prepared from the aerial photographs. The areas shown on a soil map are called mapping units. On most maps detailed enough to be useful in planning management of farms and fields, a mapping unit is nearly equivalent to a soil type or a phase of a soil type. It is not exactly equivalent, be- cause it is not practical to show on such a map all the small, scattered bits of soil of some other kind that have been seen within an area that is dominant- ly of a recognized soil type or soil phase. In preparing some detailed maps, the soil scien- tists have a problem of delineating areas where dif- ferent kinds of soils are so intricately mixed or occur in such small individual tracts that it is not practical to show them separately on the map. They show such a mixture of soils as one mapping unit and call. it a soil complex. Ordinarily, a soil complex is named for the major kinds of soils in it, for ex- ample, Cramer-Isaac gravelly clay loams, 12 to 40 percent slopes. Most surveys include areas where the soil materi- al is so rocky, so shallow, or so frequently worked by wind and water that it cannot be classified by soil series. Such an area is shown on the map like other mapping units, but it is given a descriptive name, such as Volcanic rock land or Tidal flats, and is called a land type. While a soil survey is in progress, samples of soils are taken, as needed, for laboratory measure- ments and for engineering tests. Laboratory data from the same kinds of soils in other places are as- sembled. Data on yields of crops under defined practices are assembled from farm records and from field and plot experiments on the same kinds of soils. Yields under defined management are esti- mated for all the soils. But only part of a soil survey is done when the soils have been named, described, and delineated on the map and the laboratory data and yield data have been assembled. The mass of detailed information then needs to be organized in such a way that it is readily useful to different groups of readers, among them farmers, ranchers, managers of woodland, engi- neers, and homeowners. Grouping soils that are sim- ilar in suitability for each specified use is the method of organization commonly used in soil sur- veys. The soil scientists set up trial groups based on the yield and practice tables and other data. They test these groups by further study and by con- sultation with farmers, agronomists, engineers, and others: then they adjust the groups according to the results of their studies and consultation. Thus, the groups that are finally evolved reflect up-to- date knowledge of the soils and their behavior under present methods of use and management. GENERAL SOIL MAP The general soil map in this publication shows, in color, the soil associations on the Virgin Is- lands. A soil association is a landscape that has a distinctive proportional pattern of soils. It nor- mally consists of one or more major soils and at least one minor soil, and it is named for the major soils. The soils in one association may occur in another, but in a different pattern. A map showing soil associations is useful to peo- ple who want a general idea of the soils on the is- lands, who want to compare different parts of the islands, or who want to know the location of large tracts that are suitable for a certain kind of land use. Such a map is a useful general guide in manag- ing a watershed, a wooded tract, or a wildlife area, or in planning engineering works, recreational fa- cilities, and community developments. It is not a suitable map for planning the management of a farm or field, or for selecting the exact location of a road, building, or similar structure, because the soils in any one association ordinarily differ in slope, depth, stoniness, drainage, and other charac- teristics that affect management. The general soil map of the Virgin Islands and a table that shows limitations of the major soils and degrees of limitation for selected uses are in an envelope at the back of this survey. The seven soil associations on the Virgin Islands are described in the following paragraphs. 1. Descalabrado-Jacana Association Strongly sloping to steep, well-drained soils; clay joam to clay subsoil; shallow and moderately deep over volcanic rock; on mountainsides and foot slopes This association is characterized by steep, rug- ged, forested or pastured mountain slopes slightly rounded at the top; strongly sloping, pastured or cultivated foot slopes; and valleys made up of thin alluvial fans and narrow flood plains. It occurs on the island of St. Croix. The largest acreage is in the northwestern part of the island. A smaller acreage occurs in the eastern part, on either side of Christiansted. This association makes up 19 percent of the total land area of the Virgin Islands. It is 80 percent Descalabrado soils and 15 percent Jacana soils. Descalabrado soils are on hillsides and mountain- sides throughout the association. They are steep, shallow, neutral soils that formed in material weathered in place from volcanic rock. Jacana soils are on foot slopes and alluvial fans below Descalabrado soils. They are moderately deep over volcanic rock and are slightly acid to mildly alkaline, San Anton and Cramer soils are minor soils in this association. San Anton soils are on narrow alluvial fans below Descalabrado and Jacana soils. Cramer soils are on hillsides and mountainsides. Descalabrado and Jacana soils are limited largely to use for pasture, woodland, wildlife, and recrea- tion. Shallowness over rock and steep slopes gener- ally preclude cultivation of these soils and cause them to have severe limitations for residential, commercial, and industrial development. 2. Aguilita-Fredensborg-Sion Association Gently sloping to steep, well-drained soils; clay loam and silty clay loam material below the surface woe ane Sity Shay soam material below the surface layer; shallow over soft, marly limestone; on hills, foot slopes, and terraces This association is characterized by strongly Sloping, low, rounded, forested or pastured lime- stone hills and gently sloping foot slopes and ter- races. It takes in the southwestern tip of St. Croix and much of the coastal plain in the central part of the island. This association makes up 22 percent of the total land area of the Virgin Islands, It is 50 percent Aguilita soils, 20 percent Fredensborg soils, and 20 percent Sion soils. Aguilita soils are undulating to steep, shallow, gravelly, calcareous, well drained, and moderately permeable. They formed in material weathered in place from soft limestone. Fredensborg soils are on foot slopes and in val- leys below the limestone hills. They are well drained and are shallow over soft limestone or marl. They formed in calcareous clayey sediments. Sion soils are on foot slopes and in valleys be- low Aguilita soils. They are well drained and mod- erately permeable and are shallow over soft lime- Stone or marl. They formed in calcareous material. Coamo, Diamond, and Hesselberg soils and Lime- stone rock land make up minor parts of this associa- tion. The soils are on stream terraces or alluvial fans on the coastal plains. Aguilita soils have severe limitations, chiefly steep slopes and shallowness over rock, that make them generally unsuitable for cultivated crops. Their use is limited largely to pasture and wood- land. Fredensborg and Sion soils have moderate lim- itations, chiefly slope, but they can be used for cultivated crops. Fredensborg and Sion soils have moderate limitations for most nonfarm uses, and Aguilita soils, moderate to severe limitations. 3. Fraternidad-Aguirre-Glynn Association Nearly level to gently sloping, well-drained to aearay “eve’ to gently sloping, well-~drait poorly drained, deep, mainly clayey soils on allu- vial fans This association is characterized by broad allu- vial fans that slope gently from the base of the volcanic mountains onto the coastal plain. It is dissected by many intermittent streams. It occurs on the island of St. Croix. This association makes up 8 percent of the total land area of the Virgin Islands. It is 60 percent Fraternidad soils, 15 percent Aguirre soils, and 15 percent Glynn soils. Fraternidad soils are on slightly convex alluvial fans. They are nearly level to gently sloping, deep, moderately well drained, slowly permeable, plastic clays that swell when wet and shrink when dry. They formed in clay sediments. Aguirre soils are on slightly concave alluvial fans. They are nearly level, deep, poorly drained, slowly permeable clays that swell when wet and shrink when dry. They formed in clay sediments. Glynn soils are on foot slopes and fans below the volcanic hills and along the northern edge of the coastal plain in the southern and central parts of St. Croix. They are deep, well drained, and moder- ately slowly permeable. They formed in clay and clay loam sediments. San Anton and Coamo soils are minor soils in this association. San Anton soils are ‘on narrow alluvial fans, close to the volcanic hills. Coamo soils are on stream terraces or alluvial fans at the outlets of upland drains. Fraternidad, Aguirre, and Glynn soils can be used for cultivated crops and pasture, but their heavy plastic clay ‘texture is a moderate limitation that reduces the choice of crops. Because of slow perme- ability and the shrinking and swelling of the clay, Fraternidad and Aguirre soils have severe limita- tions for residential, commercial, and industrial development. Glynn soils have moderate limitations. 4. Southgate-Parasol Association Steep to sloping, well-drained soils; gravelly loam to clay subsoil; shallow and deep over weathered granitic rock; on mountainsides, foot slopes, and alluvial fans This association is characterized by steep, rug- ged, forested or pastured mountainsides; sloping, pastured or cultivated foot slopes; and valleys made up of thin alluvial fans and very narrow flood plains. It occurs as one small area on the island of St. Croix. This association makes up 2 percent of the total land area of the Virgin Islands. It is 65 percent Southgate soils and 30 percent Parasol soils. Southgate soils are on hills and mountains. They are steep, well drained, and moderately permeable and are shallow over hard granitic rock. They formed in material weathered in place from coarse- textured rock, The subsoil is 50 percent rock frag- ments. Parasol soils are on foot slopes and alluvial fans below Southgate soils. They are deep and well drained, They are moderately permeable in the sur- face layer and moderately rapidly permeable in the subsoil. They formed in clayey sediments and mate- rial weathered from granitic rock. San Anton and Descalabrado soils are minor soils in this association. San Anton soils are on narrow alluvial fans and flood plains below Southgate and Parasol soils. Descalabrado soils are on hillsides and mountainsides. Southgate soils have severe limitations, chiefly shallowness over rock and steep slopes, that make them unsuitable for cultivation and for nonfarm uses. They are limited largely to use for pasture, woodland, wildlife habitat, and recreation. Parasol soils and the minor soils in this association, which occur on foot slopes, have moderate limitations for cultivation and for nonfarm uses. 5. Cramer-Isaac Association Very steep to strongly sloping, well-drained soils; clayey in subsoil; shallow and moderately deep over volcanic rock; on mountainsides and foot slopes This association is characterized by steep and very steep mountainsides, strongly sloping foot slopes, and narrow alluvial fans and flood plains. The soils are reddish. The surface layer is grav- elly and stony. Between 50 and 70 percent of the surface is covered with rock outcrops, and boulders and stones are common. All of the island of St. John, all of the offshore islands, a large part of the island of St. Thomas, and three fairly large areas on the island of St. Croix are in this asso- ciation. This association makes up 41 percent of the total land area of the Virgin Islands. It is 60 percent Cramer soils and 30 percent Isaac soils. Cramer soils are on mountainsides throughout the association. They are steep and very steep, shallow, red or reddish brown, well drained, and moderately permeable. Their surface layer is gravelly or stony. They formed in material weathered in place from volcanic rock. Isaac soils are on foot slopes. ly sloping, moderately deep, and well drained. have many angular volcanic rock fragments on the surface. They formed in material weathered in place from volcanic rock. Minor soils in this association are San Anton, Glynn, and Aguilita soils and Cobbly alluvial land. San Anton and Glynn soils are on narrow alluvial fans and flood plains below Cramer and Isaac soils. Aguilita soils are on low hills and foot slopes. Cobbly alluvial land is on narrow flood plains. Cramer and Isaac soils have severe limitations, chiefly shallowness over rock and steep slopes, that make them unsuitable for cultivation and for most nonfarm uses. They are limited largely to use for pasture and range, woodland, wildlife habitat, and recreation. They are strong- They 6. Dorothea-Victory-Magens Association Steep and very steep, well-drained, deep soils; clay to clay loam subsoil; on mountainsides This association is characterized by steep and very steep, rugged, forested or pastured mountains that are slightly rounded at the top. It occurs only on the island of St. Thomas. The highest peaks of the island--Hawk Hill, Crown Mountain, and Signal Hill--are on this association. This association makes up 2 percent of the total land area of the Virgin Islands. It is 60 percent Dorothea soils, 25 percent Victory soils, and 10 percent Magens soils. All of the major soils are on mountainsides. Victory and Magens soils are steep. Dorothea soils are steep and very steep. All are deep, well drained, and moderately permeable, and all formed in material derived in place from highly weathered vol- canic rock. Dorothea and Victory soils are yellow- ish brown, and Magens soils are red in the subsoil. Cramer and Isaac soils are minor soils in this association. Cramer soils are on hillsides and mountainsides. Isaac soils are on foot slopes. Dorothea, Victory, and Magens soils have severe limitations, chiefly slope, that make them unsuita- ble for cultivation. Rock terraces that can be cul- tivated satisfactorily have been constructed on some areas of Dorothea soils. The deep soils in this as- sociation can be leveled and dug into with machin- ery, and thus the slope limitation for some nonfarm uses, such as homesites, can be overcome. For the most part, however, the use of these soils is limit- ed to pasture, woodland, wildlife habitat, and rec- reation. 7. Cornhill-Coamo-San Anton Association Nearly level to gently sloping, moderately well drained and well drained, deep soils; clay to clay loam subsoil; on alluvial fans and flood plains This association occurs only .on the island of St. Croix. It consists of a strip of gently sloping al- luvial fans that extends from Southgate Pond on the north to Great Pond on the south and then extends west along the coastal plain. This association makes up 6 percent of the total land area of the Virgin Islands. It is 35 percent Cornhill soils, 30 percent Coamo soils, and 30 per- cent San Anton soils. Cornhill soils are in the southern part of the island. They are nearly level, deep, and moderately well drained. They have a moderately slowly permea- ble surface layer and slowly permeable underlying material that swells when wet and shrinks when dry. They formed in calcareous, clayey sediments mixed with varying amounts of gravel. Coamo soils are on foot slopes and alluvial fans below the limestone and volcanic hills. They are deep, well drained, moderately permeable in the sur- face layer, and moderately slowly permeable in the subsoil. They formed in calcareous clayey sedi- ments. San Anton soils are on flood plains. They are deep, well drained, and moderately permeable. They formed in neutral to slightly alkaline material de- posited on the flood plains. Descalabrado and Jacana soils are minor soils in this association. Descalabrado soils are on hill- sides and mountainsides. Jacana soils are on foot slopes below Descalabrado soils. Cornhill, Coamo, and San Anton soils are not suitable for cultivation, because of the dry cli- mate. Their use is limited largely to pasture and range, woodland, wildlife habitat, and recreation. DESCRIPTIONS OF THE SOILS This section describes-the soil series and map- ping units of the Virgin Islands. The approximate acreage and the proportionate extent of each map- ping unit are given in table 1. A general description of each soil series is given, and this is followed by brief descriptions of the mapping units in that series. For full information on any one mapping unit, it is neces- sary. to read the description of the soil series as well as the description of the mapping unit. Each series contains a short description of a typ- ical soil profile and a much more detailed descrip- tion of the same profile that scientists, engineers, and others can use in making highly technical inter- pretations. Following the name of each mapping unit is a symbol in parentheses. This symbol identifies the mapping unit on the detailed soil map. Listed at the end of the description of each mapping unit are the capability unit, the woodland group, and the range site in which the mapping unit has been placed. The page on which each capability unit, each woodland group, and each range site is des- cribed can be found readily by referring to the "Guide to Mapping Units" at the back of this survey. Many terms used in the soil descriptions and other sections of the survey are defined in the Glossary. Aguilita Series The Aguilita series consists of gently sloping to steep, well-drained soils that are shallow over soft limestone or marl. These soils formed in residuum derived from limestone. They occur in hilly and mountainous areas of St. Croix and in the northern part of St. Thomas. The slope gradient is 2 to 60 percent. The climate is semiarid. The average annual rainfall is between 30 and 45 inches, and the average annual temperature is between 78° and 80° F. In a typical profile (pl. I) the surface layer is very dark grayish-brown and light brownish-gray grav- elly clay loam about 6 inches thick. Below this is mixed very dark grayish-brown and dark grayish-brown, firm, calcareous gravelly clay loam that is 50 to 70 percent limestone fragments. The substratum, at a depth of about 10 inches, is mostly soft lime- stone but contains hard limestone concretions. The soft: limestone material can be penetrated with a spade. Drainage is good, and permeability is moderate. The water table is low. Most of the acreage is in grasses and brush. A small acreage has been cleared and is now in guinea- grass and is used as pasture. Representative profile of Aguilita graveily clay loam, 20 to 40 percent slopes, in a brushy area on St. Croix, half a mile north and 125 feet west of an interséction three-fourths of a mile east of In- sular Experiment Station: A--0 to 6 inches, mixed very dark grayish-brown (10YR 3/2) and light brownish-gray (10YR 6/2) gravelly clay loam; moderate, fine, subangular blocky structure; slightly hard, firm, slightly sticky, slightly plastic; approximately 50 percent limestone rock fragments; calcareous; common fine roots; clear, smooth boundary. 3 to 8-inches thick. to 10 inches, mixed very dark-grayish-brown (1OYR 3/2) and dark grayish-brown (10YR 4/2) gravelly clay loam; weak, fine, granular structure; firm; 50 to 70 percent limestone fragments; calcareous; few fine roots; grad- ual, smooth boundary. 1 to 6 inches thick. to 60 inches +, white (10YR 8/1) soft lime- stone or marl; few to common hard limestone concretions. AC--6 C--10 The depth to soft limestone or marl ranges: from 4 to 14 inches. The number of limestone fragments ranges from common to many. The color of the A hori- zon ranges from very dark grayish brown (10YR 3/2) to dark yellowish brown (10YR 3/4) or light brownish gray (10YR 6/2), and the texture ranges from grav- elly clay loam to gravelly clay. The color of the AC horizon ranges from very dark grayish brown (10YR 3/2) to brown (10YR 5/3), and the texture from grav- elly clay loam to gravelly clay. This horizon also contains pockets that have weak blocky structure. The color ranges from white to light gray. Aguilita soils are shallower and more gravelly than Sion and Fredensborg soils. They lack the weakly expressed B horizon and the horizon of accu- Mulated calcium carbonate that are typical of Pozo Blanco soils. . They are not so red as Hesselberg. and Diamond soils. Aguilita gravelly clay loam, 2 to 5 percent slopes (AgB).--This soil is on ridges and knolis in the southern and southwestern parts of St. Croix. Included in mapping were spots of Diamond clay loam and Hesselberg clay. The surface layer of this Aguilita soil is dom- inantly very dark grayish brown and is 4 to 6 inches thick. The texture is gravelly clay loam to a depth of 10 to 14 inches. This soil can be used occasionally for cultivated crops. It has a moderate limitation as a site for picnic areas, trafficways, highways, and airports, for buildings for light industry, and for residences served by a community sewerage system. (Capability unit IVe-1; woodland group 2; Shallow range sites 6 and 9, precipitation zones 35 to 45 inches and 25 to 35 inches) Aguilita gravelly clay loam, 5 to 12 percent slopes, eroded (AgC2).--This soil is on ridges and foot slopes in the southern and southwestern parts of St. Croix. Included in mapping were small areas of Fredensborg, Sion, and Diamond soils. As a result of erosion, the surface layer of this Aguilita soil is now only 3 to 5 inches thick. It is lighter colored than that in the profile de- scribed as typical for the series because it has TABLE 1.--APPROXIMATE ACREAGE AND PROPORTIONATE EXTENT OF THE SOILS Soil Aguilita gravelly clay loam, 2 to 5 percent slopes------------------- Aguilita gravelly clay loam, 5 to 12 percent slopes, eroded-------- Aguilita gravelly clay loam, 12 to 20 percent slopes---------------- Aguilita gravelly clay loam, 20 to 40 percent slopes---~------------- Aguilita gravelly clay loam, 40 to 60 percent slopes---------------- Aguirre clay, 0 to 2 percent s lopes ------------- 9-2 - enn noone slopes--------------------------- Cobbly alluvial land--------------- Cornhill gravelly clay loam, 0 to 2 percent slopes------------------- Cramer gravelly clay loam, 5 to 12 percent slopes------------------- Cramer gravelly clay loam, 12 to 40 percent slopes----~-~-------------- Cramer gravelly clay loam, 40 to 60 percent slopes------------------- Cramer stony clay loam, 12 to 40 percent slopes, eroded------------ Cramer stony clay loam, 40 to 60 percent slopes, eroded----~--~---- Cramer-Isaac gravelly clay loams, 12 to 40 percent slopes---------- Descalabrado clay loam, 12 to 20 percent slopes------------------- Descalabrado clay loam, 20 to 40 percent slopes------------------- Descalabrado clay loam, 40 to 60 percent slopes-----~-------~------- Diamond-Limestone rock land com- plex, 0 to 5 percent slopes------ Diamond-Limestone rock land com- plex, 5 to 12 percent slopes, Dorothea clay loam, 20 to 40 per- cent slopes-------~---- Se atetalenetenetated Dorothea clay loam, 40 to 60 per- cent slopes---------------------- Fraternidad clay, 0 to 3 percent SlopeS----------- enn nnn nner ene Fraternidad clay. 3 to 12 percent slopes, eroded-----------~------- Fredensborg clay, 0 to 2 percent Ss lopes-~----------2e- oon nnn ne slopes ~--------- 7-9 n-ne nnn nnn- Fredensborg clay, 5 to 12 percent slopes, eroded-------- fener en-n-- Glynn clay loam, 2 to 5 percent slopes -------------------9------- Glynn clay loam, 5S to 12 percent slopes, eroded------------------- less than 0.05 percent. Isaac clay saprolitic sub- stratum, 40 percent Isaac gravelly clay loam, 5 to 20 percent slopes Jacana clay loan, Lavallee gravelly percent slopes Leveled clayey land Leveled marly land Leveled rocky land Limestone rock land Made land Magens silty clay loam, 30 to 50 percent slopes Parasol clay loam, 2 to 5 percent Pozo Blanco clay loam, 5 to 12 per- cent slopes Pozo Blanco clay loam, 12 to 20 percent slopes San Anton clay loam, San Anton clay loam, cent slopes Sion clay loam, 0 to 5 percent s lopes+-----------~--------------- Sion clay loam, 5 to 12 percent Southgate clay loam, cent slopes Southgate clay loam, cent slopes Southgate-Rock land complex, 20 to 60 percent slopes Tidal flats Tidal swamp Victory clay loam, 12 to 20 percent been mixed with material weathered from the under- lying gray limestone. The texture is gravelly clay loam to a depth of 8 to 12 inches. This soil is not suited to cultivated crops; it is shallow and is low in water-holding capacity. It has a moderate limitation as a site for highways, airports, and buildings for light industry, but only a slight limitation for trafficways. and for resi- dences served by a community sewerage system. (Capability unit VIe-3; woodland group 2; Shallow range sites 6 and 9, precipitation zones 35 to 45 inches and 25 to 35 inches) Aguilita gravelly clay loam, 12 to 20 percent slopes (AgD).--This soil occurs on ridgetops and side slopes in the southern and southwestern parts of St. Croix and in the north-central part of St. Thomas. Included in mapping were small areas of Limestone rock land, bands of Sion clay loam, and, north of the Truman Airport in St. Thomas, small areas of soils that developed in calcareous vol- canic rocks. The surface layer of this Aguilita soil is dom- inantly dark grayish brown and is more than 5 inches thick. The texture is gravelly clay loam to a depth of 10 to 14 inches. This soil has severe limitations, mainly shallow- ness and strong slopes, that preclude its use for cultivated crops, but it can be used safely for pas- ture or woodland, It has a moderate limitation as a site for picnic areas and trafficways and for res- idences served by a community sewerage system. It has a severe limitation as a site for highways, air- ports, and buildings for light industry. (Capability unit VIe-3; woodland group 2; Shallow range sites 6 and 9, precipitation zones 35 to 45 inches and 25 to 35 inches) Aguilita gravelly clay loam, 20 to 40 percent slopes (AgE).--This soil is on side slopes in the southern and southwestern parts of St. Croix and in the north-central part of St. Thomas. Included in mapping were small areas of Limestone rock land. This Aguilita soil has the profile described as representative for the series. The depth to soft limestone ranges from 8 to 12 inches. This soil can be used for woodland or pasture. Shallowness, moderately steep slopes, and rapid run- off preclude cultivation, and shallowness and slope severely limit nonfarm uses. (Capability unit VIIe-1; woodland group 2; Shallow range sites 6 and 9, precipitation zones 35 to 45 inches and 25 to 35 inches) Aguilita gravelly clay loam, 40 to 60 percent slopes (AgF).--This steep soil is in the central part of St. Croix and in the northern part of St. Thomas. Included in mapping, and making up 15 to 20 percent of some mapped areas, were tracts of Limestone rock land. The surface layer of this Aguilita soil is 3 to 5 inches thick and is grayish brown to dark grayish brown in color. The texture is gravelly clay loam to a depth of 4 to 10 inches. Shallowness, rapid runoff, and steep slopes se- verely limit almost all farm and nonfarm uses. Es- tablishing and maintaining pasture is more difficult on this soil than on other soils in the Aguilita series. (Capability unit VIIe-1; woodland group 2; Shallow range sites 6 and 9, precipitation zones 35 to 45 inches and 25 to 35 inches) Aguirre Series The Aguirre series consists of nearly level to slightly depressed, poorly drained soils that are deep over limestone and volcanic :rocks. These soils formed in clayey sediments derived from these rocks. They occur near codstal areas and on valley floors on the island of St. Croix. The slope gradient is 0 to 2 percent. The climate is semiarid. The aver- age annual rainfall is between 30 and 45 inches, and the average annual temperature is between 78° and 80° F. In a typical profile the surface layer is very dark gray clay about 13 inches thick. Below this is dark-gray and light olive-brown, firm and very firm, calcareous clay that shrinks when dry and swells when wet. The substratum, at a depth of about 36 inches, is olive-gray and light olive-brown clay. Orainage is poor, and permeability is slow. Most of the acreage is cultivated. Representative profile of Aguirre clay, 0 to 2 percent slopes, three-tenths of a mile north and 50 feet west of Bethlehem sugar factory, on St. Croix: All--0 to 10 inches, verv dark gray (N 3/0) clay; massive when wet; moderate, fine, granu- lar structure when dry; hard, very firm, sticky, plastic; common fine roots; cal- careous; gradual, wavy boundary. 7 to 11 inches thick. Al2--10 to 13 inches, very dark gray (N 3/0) clay; Massive; many pressure faces and slicken- sides; very hard, very firm, sticky, plastic; few fine roots; few black concretions; calcareous; clear, wavy boundary. 3 to 10 inches thick. Al3--13 to 26 inches, dark-gray (5Y 4/1) clay; medium and coarse, wedge-shaped peds and many pressure faces and slickensides; very hard, very firm, sticky, plastic; few fine roots; few fine fragments of volcanic rock; few, fine, black concre- tions; strongly calcareous; clear, irreg- ular boundary. 6 to 13 inches thick. AC--26 to 36 inches, mixed light olive-brown (2.5Y 5/4) and dark-gray (5Y 4/1} clay; massive; many, medium and coarse, wedge- shaped peds and common pressure faces and slickensides; very hard, firm, sticky, plastic; calcareous; clear, ir- regular boundary. 5 to 12 inches thick. Cl1--36 to 45 inches, olive-gray (SY 5/2) clay; massive; few, medium and coarse, ‘wedge- shaped peds and common pressure faces and slickensides; very hard, very firm, slightly sticky, plastic; few, fine, black concretions; calcareous; gradual, wavy boundary. 7 to 12 inches thick. C2--45 to 60 inches, light olive-brown (2.5Y 5/4) clay; massive; pressure faces and small slickensides; very hard, very firm, slightly sticky, plastic; few, fine, black concretions; calcareous. There are few to common black concretions and volcanic rock fragments throughout the profile. The color of the A horizon ranges from black (N 2/0) to very dark gray (N 3/0, 10YR 3/1, SY 3/1) and dark gray (5Y 4/1). This layer is massive when wet but has weak to moderate granular structure when dry. The color of the AC and C horizons ranges from very dark grayish brown (10YR 3/2) and light olive brown (2.5Y 5/4) to olive (SY 5/4). There are few to common, low-chroma and yellowish-brown mottles. Aguirre soils are associated with Fraternidad, Coamo, Glynn, Fredensborg, and Cornhill soils. They are more poorly drained, have a darker colored profile, and have a less friable surface layer than Fraternidad soils, and they occur on concave rather than convex slopes. They are more poorly drained than Coamo soils, which formed in stratified sedi- ments of silt, clay, sand, and gravel. They are more poorly drained than Glynn soils, which have a well- developed subsoil and stratified underlying mater- ial. They are deeper than Fredensborg soils, which are shallow over soft limestone. They are more poorly drained ‘than Cornhill soils, which are clay loam in the surface layer and upper part of the sub- soil and are clayey and plastic in the lower part of the subsoil and in the substratum. Aguirre clay, 0 to 2 percent slopes (AuA).--This soil is near the Bethlehem sugar factory. Included in mapping were areas that are slightly saline and small areas that are less than 30 inches deep over marl. This Aguirre soil is used for sugarcane, but it is sticky and plastic and is difficult to keep in good tilth. Slow permeability, waterlogging, and poor workability limit all farm uses. High shrink-swell potential, slow permeability, high plasticity, and poor bearing strength severely limit nonfarm uses. (Capability unit IVw-1; no woodland classification; Deep range site 4, precip- itation zone 35 to 45 inches) Coamo Series The Coamo series consists of gently sloping, well-drained soils that are deep over volcanic and limestone rocks. These soils occur on alluvial fans and terraces. They formed in sediments derived from these rocks. The sediments range in texture from clay to sand, The slope gradient is 2 to 5 percent. The climate is semiarid, The average an- nual rainfall is between 30 and 40 inches, and the average annual temperature is between 78° and 80°F. In a typical profile the surface layer is very dark grayish-brown clay loam about 8 inches thick. It contains a few rock fragments. The subsoil is very dark grayish-brown and yellowish-brown, firm clay. It also contains a few rock fragments. The substratum, beginning at a depth of about 24 inches, is yellowish-brown and dark yellowish-brown, friable, calcareous clay loam stratified with sand and gravel. Most of the acreage is in grasses and brush. A small acreage has been cleared and is now in guinea- grass and is used as pasture. Representative profile of Coamo clay loam, 2 to 5 percent slopes, in a native pasture on St. Croix, 160 feet east and 200 feet north of a windmill that is three-tenths of a mile due north of the main en- trance to Halfpenny Bay estate: Ap--0 to 8 inches, very dark grayish-brown (10YR 3/2) clay loam, dark gray (10YR 4/1) when dry; weak, coarse, subangular blocky structure that breaks to weak, fine, sub- angular blocky; hard, friable, slightly sticky, slightly plastic; common fine roots; few angular fragments of volcanic rock 1/4 to 1/2 inch in diameter; neutral; clear, smooth boundary. 5 to 10 inches thick. B2t--8 to 14 inches, very dark grayish-brown (10YR 3/2) clay; weak, medium, subangular blocky structure; hard, firm, slightly sticky, plastic; thin, discontinuous clay films; few fine roots; many angular frag- ments of volcanic rock 1/4 to 1/2 inch in diameter; neutral; clear, smooth boundary. 6 to 12 inches thick. B3ca--14 to 24 inches, yellowish-brown (10YR 5/4) clay; weak, medium, subangular blocky structure; hard, firm, slightly sticky, plastic; few fine roots; many fragments of volcanic rock 1/4 to 1/2 inch in diam- eter; common, fine, dark-colored nodules; common medium lime splotches; strongly calcareous; gradual, smooth boundary. 8 to 16 inches thick. TIClca--24 to 40 inches, yellowish-brown (10YR 5/4) clay loam; massive; friable, slightly sticky, nonplastic; few, fine, dark- colored nodules; thin lenses 1/4 to 1/2 inch thick of fine and medium gravel; common medium lime splotches; strongly calcareous; gradual, wavy beundary. 10 to 20 inches thick. IIIC2ca--40 to 50 inches, yellowish-brown (10YR 5/6) gravelly clay loam; massive; friable, slightly sticky, nonplastic; many, fine and medium, angular fragments of volcanic rock; few, fine, dark-colored nodules; common fine lime splotches; strongly cal- careous; gradual, wavy boundary. 8 to 14 inches thick. IVC3ca--50 to 56 inches, dark yellowish-brown (10YR 4/4) clay loam; massive; friable, slightly sticky, nonplastic; few, fine, dark-colored nodules; few fine lime splotches; calcareous; abrupt, smooth boundary. 4 to 10 inches thick. vC4--56 to 60 inches +, gravel. The thickness of the solum ranges from 24 to 38 inches. The texture of the Ap horizon is dominantly clay loam but ranges to silty clay loam. The color ranges from black (10YR 2/1) or dark gray (10YR 4/1) to very dark grayish brown (10YR 3/2). The reaction ranges from neutral to slightly acid. The texture of the B horizon is dominantly clay. The color ranges from 7.5YR to 10YR in hue, 3 to 5 in value, and 2 to 6 in chroma, The structure ranges from weak, medium, subangular blocky to moderate, mediun, subangular blocky. Clay films range from few patchy to thin discontinuous. The underlying horizons are stratified gravel, gravelly clay loam, and loam. They contain varying amounts of secondary lime. Coamo soils are associated with Cornhill, San Anton, Glynn, and Fraternidad soils. They are less clayey in the underlying material than Cornhill soils are, and they do not have the large slicken- sides that are typical of those soils. They are more calcareous in the underlying material than San Anton soils, which formed in stratified sediments derived from limestone and volcanic rocks. They differ from Glynn soils in having a more friable surface layer and a thinner subsoil. They are less clayey and less plastic than Fraternidad soils. Coamo clay loam, 2 to 5 percent slopes (CaB) .-- This soil is on alluvial fans and terraces. Includ- ed in mapping were small areas of San Anton clay loam, Cornhill clay loam, and Fraternidad clay, and spots of Coamo clay loam where the gradient is 1 percent. Adverse climate is the major limitation. The lack of sufficient rainfall and the high evapora- tion rate cause crop failures, even though all other soil characteristics are favorable. Pasture grasses grow well. There are few or no limitations for most nonfarm uses. (Capability unit IIIc-1; no woodland classification; Deep range sites 1, 4, and 7, pre- cipitation zones 45 to 60 inches, 35 to 45 inches, and 25 to 35 inches) Cobbly Alluvial Land Cobbly alluvial land (Cb) occurs as gently slop- ing to moderately sloping, narrow strips near streams. It consists of sediments of varying tex- ture. The material is 60 to 75 percent subangular and subrounded, very hard cobblestones of volcanic origin. It ranges from very dark grayish brown to dark yellowish brown in color, and in spots where it is associated with Cramer soils, it is more red than is typical. At present, the acreage is in native grasses and is used as pasture. Poor workability, an overflow hazard, rapid permeability, a low water-holding ca- pacity, and stoniness severely limit all farm and nonfarm uses. (Capability unit VIIs-4; no woodland classification; no range site classification) Cornhill Series The Cornhill series consists of nearly level, moderately well drained soils that are deep over 10 clayey, plastic sediments. These soils formed in a mantle of clay loam sediments. They occur near coastal areas, on terraces and alluvial fans in the southern part of St. Croix. The slope gradient is 0 to 2 percent. The climate is semiarid. The av- erage annual rainfall is between 30 and 35 inches, and the average annual temperature is between 78° and 80° PF. In a typical profile the surface layer is dark- brown gravelly clay loam about 9 inches thick. The upper part of the subsoil is very dark brown, firm, calcareous clay loam. The lower part is dark gray- ish-brown, firm clay. It extends to a depth of about 30 inches. The underlying layers are yellow- ish-brown, calcareous clay that shrinks when dry and swells when wet. Most of the acreage is used as pasture. The vegetation consists of native grasses and shrubs. Guineagrass grows in well-managed areas. Representative profile of Cornhill gravelly clay loam, 0 to 2 percent slopes, on St. Croix, 205 feet east and 85 feet north of the southwest corner of a pasture fence that is three-tenths of a mile south of a windmill at Longford, or a little less than five-tenths of a mile south of the farm entrance: Ap--0 to 9 inches, dark-brown (10YR 3/3) gravelly clay loam, grayish brown (10YR 5/2) when dry; weak, medium, subangular blocky structure; very hard, firm, slightly sticky, slightly plastic; common, fine and medium, angular and subrounded fragments of volcanic rock; common fine roots; few, fine, black concretions; calcareous; mod- erately alkaline; clear, wavy boundary. 8 to 14 inches thick. B2--9 to 18 inches, very dark brown (10YR 2/2) heavy clay loam; weak, medium and coarse, subangular blocky structure; hard, firm, slightly sticky, slightly plastic; few, fine, dark-colored oxide concretions; cal- careous; moderately alkaline; gradual, wavy boundary. 8 to 16 inches thick. IIB3--18 to 30 inches, dark grayish-brown (10YR 4/2) clay; weak, coarse, angular blocky structure, with slickensides and pressure faces when moist, that breaks to weak, coarse, granular structure or weak, fine, subangular blocky structure when dry; firm, sticky, plastic; common, fine, black concretions; calcareous; moderately alka- line; gradual, wavy boundary. 12 to 24 inches thick. IIIC1--30 to 36 inches, yellowish-brown (10YR 5/4) gravelly clay; weak, medium and coarse, angular blocky structure, with slickensides and pressure faces when moist, that breaks to weak, medium, granular structure when dry; firm, slightly sticky, plastic; common, fine, black concretions; common, fine and medium, calcium carbonate concretions; moderately alkaline; clear, wavy boundary. 6 to 12 inches thick. IIIC2--36 to 48 inches +, yellowish-brown (10YR 5/4) gravelly clay; massive; firm, slight- ly sticky, slightly plastic; common, fine, dark-colored oxide concretions; calcareous. The thickness of the Ap and B2 horizons combined ranges from 16 to 30 inches. The profile is calcar~ eous throughout, and secondary lime is present in the lower horizons. In places sandy and gravelly lenses occur throughout the profile. The color of the A horizon ranges from very dark brown (10YR 2/2) to dark grayish brown (10YR 4/2), and the texture from gravelly clay loam to clay loam. The color of the B horizon ranges from very dark brown (10YR 2/2) and dark grayish brown (10YR 4/2) to yellowish brown (10YR 5/4). The texture is dominantly clay loam in the upper part of the profile and clay in the lower part. The structure ranges from weak, medium, sub- angular blocky to weak, coarse, subangular blocky, and there are few to common pressure faces. The consistence of the B horizon ranges from firm to friable. The C horizon is typically stratified. The upper part is plastic, dark yellowish-brown (10YR 4/4) to light yellowish-brown (10YR 6/4) clay or gravelly clay and has many slickensides and pressure faces. The lower part grades to sand and gravel at a depth of 48 to 68 inches. Cornhill soils are associated with Coamo, San Anton, and Fraternidad soils. They do not have the sandy and gravelly lenses in the lower part of the profile that are typical of Coamo soils. They have more free lime than San Anton soils. They are less clayey and less plastic throughout than Fraternidad soils. Cornhill gravelly clay loam, 0 to 2 percent. slopes (CoA).--This soil is on terraces and alluvial fans in the southern part of St. Croix. Included in mapping were very gravelly areas and spots of Coamo clay loam, San Anton clay loam, and Fraternidad clay, none of which exceed 10 percent of each mapped area. Also, along the southern coast and close to the sea are small areas of soils that contain vary- ing amounts of soluble salts. Adverse climate is the major limitation. The lack of sufficient rainfall and the high evapora- tion rate cause crop failures, even though all other soil characteristics are favorable. Pasture grasses grow well. The shrinking and swelling of the under- lying plastic clay severely limit use of this soil as a site for residences and for buildings for light industry. Limitations are moderate to severe for recreational uses, as for campsites, picnic areas, intensive play areas, and golf fairways. (Capability unit IVc-1; no woodland classification; Deep range sites 4 and 7, precipitation zones 35 to 45 inches and 25 to 35 inches} Cramer Series The Cramer series consists of moderately sloping to steep, well-drained soils that are shallow over partly weathered, basic volcanic rocks. These soils occur on side slopes of dissected volcanic uplands throughout the Virgin Islands. The slope gradient is 5 to 60 percent. The climate is semiarid. The average annual rainfall is between 30 and 55 inches, and the average annual temperature is between 78° and 80° F. In a typical profile (pl. I) the surface layer is dark reddish-brown gravelly clay loam that is 30 percent volcanic rock fragments. This layer is 9 inches thick. The upper 4 inches of the subsoil is firm, dark-red gravelly clay that also is 30 percent volcanic rock fragments. The lower 6 inches is very firm, dark reddish-brown clay. Below a depth of about 19 inches is partly altered volcanic rock. This material is difficult to dig into with a spade. Drainage is good. Runoff is medium to rapid, and permeability is moderate. About four-fifths of the acreage is gravelly, and one-fifth is stony. Most of the acreage is in brush or brushy forest. Only a small part is cultivated or used as pasture. Representative profile of Cramer gravelly clay loam, 40 to 60 percent slopes, on St. Croix, 1.8 miles northwest of junction of roads to Annaly and Scenic Drive, and 100 feet north of road or 1.3 miles northeast of rock quarry located in northwest corner of St. Croix, along Scenic Drive. Al--0 to 9 inches, dark reddish-brown (5YR 3/3) gravelly clay loam; moderate, medium, granular structure; slightly hard, fri- able, nonsticky, slightly plastic; many fine roots; 30 percent angular volcanic rock fragments 1/4 to 1/2 inch in diam- eter; neutral; clear, smooth boundary. 5 to 10 inches thick. to 13 inches, dark-red (2.5YR 3/6) grav- elly clay; weak, medium, subangular blocky structure that breaks to moderate, medium, granular; firm, slightly sticky, slightly plastic; common fine roots; 30 percent angular volcanic rock fragments 1/4 inch to 2 inches in diameter; slightly acid; clear, smooth boundary. 3 to S inches thick. B2t--13 to 19 inches, dark reddish-brown (2.S5YR 3/4) clay; moderate, fine and medium, sub- angular blocky structure; very firm, sticky, plastic; few pressure faces; many volcanic rock fragments 1/4 inch to 2 inches in diameter; medium acid; abrupt, wavy boundary. 2 to 8 inches thick. inches +, greenish-gray, hard-bedded vol- canic mudstone (very difficult to dig with spade); red and dark reddish-brown stains along fracture planes. Bl--9 R--19 The depth to hard rock ranges from 10 to 20 inches. The percentage of gravel ranges from 25 to 60. The reaction ranges from medium acid to neu- tral. The color of the A horizon is 5YR and 2.5YR in hue, 3 in value, and 2 to 4 in chroma. The tex- ture of the B2t horizon is dominantly clay. The 11 color is 5YR and 2.5YR in hue, 3 and 4 in value, and 4 to 8 in chroma. The structure is weak to moder- ate, coarse to fine, subangular blocky. Cramer soils are associated with Descalabrado, Southgate, Victory, Magens, and Dorothea soils. They are redder and more plastic than Descalabrado soils, which. are neutral to mildly alkaline. They are redder and more clayey in the subsoil than South- gate soils, which developed in material weathered from granitic rocks. They are less yellow than Victory soils. They have a more strongly developed subsoil than Southgate and Victory soils. They are less red, are shallower, and have a thinner subsoil than Magens soils. They are less yellow and are shallower than Dorothea soils, which are underlain by softer, more altered rock. Cramer gravelly clay loam, 5 to 12 percent slopes (CrC).--This soil is on small hills near the north- ern coast of St. Croix, east of Christiansted, and also occurs as scattered areas on the islands of St. Thomas and St. John. Included in mapping, and making up 10 to 15 percent of each mapped area, were spots of Isaac gravelly clay loam. The surface layer of this Cramer soil is 8 to 10 inches thick. Bedrock is at a depth of 12 to 20 inches. This soil is suitable for pasture and woodland and is used for those purposes. Moderate slopes, susceptibility to erosion, shallowness over rock, a large amount of gravel throughout the profile, and a low water-holding capacity are severe limita- tions that preclude its use for cultivated crops. It has a moderate limitation as a site for picnic areas and trafficways, and a severe limitation as a site for residences, intensive play areas, camps, golf fairways, and buildings for light industry. (Capability unit VIs-3; woodland group 4; Shallow range sites 6 and 9, precipitation zones 35 to 45 inches and 25 to 35 inches) Cramer gravelly clay loam, 12 to 40 percent slopes (CrE).--This soil iS on the ridges and side slopes of dissected volcanic uplands throughout the Virgin Islands. Included in mapping, and making up 10 to 1S percent of each mapped area, were spots of Isaac gravelly clay loam, Descalabrado clay loam, Dorothea clay loam, and Victory clay loam, and spots where the underlying volcanic rock contains second- ary lime. The surface layer of this Cramer soil is 7 to 9 inches thick. The depth to hard rock ranges from 10 to 20 inches. This soil is suitable for pasture and woodland, and the entire acreage is used for those purposes. Shallowness over rock, moderately steep slopes, sus- ceptibility to erosion, a large number of coarse fragments, and a low water-holding capacity preclude cultivation. Limitations are severe for nonfarm uses, as for residences, buildings for light industry, trafficways, campsites, picnic areas, intensive play areas, and golf fairways. (Capabil- ity unit VIs-3; woodland group 4; Shallow range sites 6 and 9, precipitation zones 35 to 45 inches and 25 to 35 inches) 12 Cramer gravelly clay loam, 40 to 60 percent slopes (CrF).--This soil is on the side slopes of dissected volcanic uplands throughout the Virgin Islands. Included in mapping, and making up 10 to 15 percent of the total acreage, were spots of Cramer stony clay loam, Descalabrado clay loam, Dorothea clay loam, Isaac gravelly clay loam, and Volcanic rock land, and areas where the underlying rock is coated with secondary lime. Small pockets of gravelly colluvium occur on the lower slopes. This Cramer soil has the profile described as representative for the series. The surface layer is 5 to 9 inches thick. The depth to hard rock ranges from 13 to 20 inches. Steep slopes, shallowness over rock, rapid run- off, susceptibility to erosion, and the large number of coarse fragments throughout the profile preclude cultivation and make it difficult to establish and maintain pasture. These limitations also preclude nonfarm uses. (Capability unit VIIs-3; woodland group 4; Shallow range sites 6 and 9, precipitation zones 35 to 45 inches and 25 to 35 inches) Cramer stony clay loam, 12 to 40 percent slopes, eroded (CsE2).--This soil is on the ridges and side slopes of dissected volcanic uplands in the eastern part of St. Croix and throughout the islands of St. Thomas and St. John. Included in mapping were small areas of Volcanic rock land and of Cramer gravelly clay loam. From 50 to 70 percent of the surface of this Cra- mer soil is covered with stones and cobblestones. The stones are 1 foot to 3 feet in diameter. The surface layer is 5 to 8 inches thick. The depth to hard rock ranges from 10 to 20 inches. Most of the acreage is forest or brushy forest. Shallowness over rock, moderately steep slopes, stoniness, poor workability, and rapid runoff pre- clude cultivation. Stoniness makes it difficult to establish and maintain pasture. Limitations are se- vere for nonfarm purposes, as for residences, build- ings for light industry, campsites, picnic areas, intensive play areas, and golf fairways. (Capabil- ity unit VIIs-1; no woodland classification; Shallow range sites 6 and 9, precipitation zones 35 to 45 inches and 25 to 35 inches) Cramer stony clay loam, 40 to 60 percent slopes (CsF).--This soil occurs on the side slopes of dis- sected volcanic uplands on the island of St. John, as small areas on St. Thomas, and as a very small acreage on south-facing slopes east of Christian- sted, on the island of St. Croix. Included in map- ping were small areas of Volcanic rock land and Cramer gravelly clay loam. From 50 to 70 percent of the surface of this Cramer soil is covered with stones and cobblestones. The stones are 1 foot to 3 feet in diameter. The surface layer is 5 to 9 inches thick. The depth to hard rock ranges from 10 to 20 inches. Almost all of the acreage is forest or brushy forest. Very steep slopes, shallowness over rock,a large number of stones on the surface, rapid runoff, and a limited water-holding capacity severe- ly limit use of this soil for cultivated crops and make it difficult to establish and maintain grasses for pasture. Limitations are also severe for non- farm purposes, as for residences, buildings for light industry, trafficways, campsites, picnic areas, intensive play areas, and golf fairways. (Capabil- ity unit VIIs-1; no woodland classification; Shallow range sites 6 and 9, precipitation zones 35 to 45 inches and 25 to 35 inches) Cramer-Isaac gravelly clay loams, 12 to 40 per- cent slopes (CvE).--These soils occupy side slopes, foot slopes, and concave colluvial-alluvial positions along drains. They occur throughout the islands of St. Thomas and St. John. Isaac soils make up 30 to 45 percent of each mapped area. Cramer soils have a surface layer of gravelly clay loam and a subsoil of gravelly clay. Hard rock is at a depth of 10 to 20 inches. Isaac soils are thicker than Cramer soils and have hard rock at a depth of 20 to 40 inches. A description of Isaac soils is given under the heading "Isaac Series." Moderately steep slopes, coarse fragments, and shallowness over rock are limitations that preclude the use of these soils for cultivated crops and make them unsatisfactory for residences, buildings for light industry, trafficways, campsites, intensive play areas, and golf fairways. Isaac soils are more productive of grasses than Cramer soils. (Capability unit VIe-1; woodland group 4; no range site classi- fication) Descalabrado Series The Descalabrado series consists of strongly sloping to steep, well-drained soils that are shal- low over consolidated, basic volcanic rocks. These soils formed in clay loam material derived from the rocks. They occur on mountainous terrain. The slope gradient is 12 to 60 percent. The climate is semiarid. The average annual rainfall is between 30 and 45 inches, and the average annual temperature is between 78° and 80° F. In a typical profile the surface layer is very dark grayish-brown clay loam about 6 inches thick. The subsoil extends to a depth of about 14 inches. The upper part is brown, friable clay loam, and the lower part is dark-brown, firm silty clay. Below this is olive-brown, decomposed volcanic rock in which the original rock structure is still evident. This material can be penetrated easily with a. spade. It is underlain, at a depth of less than 20 inches, by hard, greenish-gray volcanic rock. Most of the acreage is in native grasses and is used as pasture. Representative profile of Descalabrado clay loam, 20 to 40 percent slopes, in a native pasture on St. Croix, 1.6 miles west of the intersection of Scenic Drive and the road from La Vallee to River and 50 feet east of the read: Ap--0 to 6 inches, very dark grayish-brown (10YR 3/2) clay loam; weak, fine, subangular blocky structure to moderate, medium, granular; friable, slightly sticky, slightly plastic; many fine roots; few fine volcanic fragments; neutral; clear, smooth boundary. 3 to 7 inches thick. Bl--6 to 10 inches, brown (10YR 4/3) clay loam; mod- erate, fine, subangular blocky structure; friable, slightly sticky, slightly plastic; many fine roots; few fine volcanic fragments; neutral; clear, smooth boundary. 2 to 4 inches thick. to 14 inches, dark-brown (10YR 4/3) light silty clay; moderate, fine and medium, sub- angular blocky structure; firm, nonsticky, slightly plastic; thin, very dark grayish- brown (10YR 3/2) clay films; common fine roots; few fine volcanic fragments; few dark- colored worm casts; 10 to 15 percent sapro- lite; neutral; clear, smooth boundary. 3 to S inches thick. C--14 to 19 inches, olive-brown (2.5Y 4/4) loam (saprolite); fracture planes of the original rock structure coated with dark-brown (10YR 3/3) clay and organic matter. 2 to 5 inches thick. R--19 inches +, greenish-gray, slightly weathered volcanic rock. B2--10 The depth to consolidated rock ranges from 10 to 20 inches. Volcanic rock fragments range from few to common throughout the profile. The texture of the A horizon is dominantly clay loam but ranges from silty clay loam to loam. The color ranges from very dark grayish brown (10YR 3/2) and very dark brown (10YR 2/2) to dark brown (10YR 3/3 or 7.5YR 3/2). The texture of the B horizon ranges from clay loam, silty clay loam, and silty clay to gravelly clay loam, and the color from dark brown (10YR 3/3) and brown (10YR 4/4) to strong brown (7.5YR 5/6). The structure ranges from weak, fine and medium, subangular blocky to moderate, fine and medium, sub- angular blocky. The reaction is neutral. Descalabrado soils are associated with Victory, Cramer, Southgate, Jacana, Pozo Blanco, and Diamond soils and Volcanic rock land. They are slightly shallower, are less deeply altered, and have a thin- ner subsoil than Victory soils. They are less clay- ey, are less red, and have a less strongly developed subsoil than Cramer soils. They are less acid and less gravelly than Southgate soils. They are less clayey and are shallower over hard rock than Jacana soils. They are shallower than Pozo Blanco soils, which are calcareous in the lower part of the sub- soil and formed in limy material. They are not so red as Diamond soils, which overlie hard limestone. Descalabrado clay loam, 12 to 20 percent slopes (DeD).--This soil occurs on side slopes and ridge- tops in the western part of St. Croix, north of Frederiksted, and in the eastern part, south and east of Christiansted. Included in mapping were spots of Jacana clay loam, San Anton clay loam, and Victory clay loam. The surface layer of this Descalabrado soil is 5 to 7 inches thick. The depth to rock ranges from 16 to 20 inches. iS This soil is suited to pasture and woodland but is used mostly for pasture. It has limitations, mainly shallowness over rock, strong slopes, and an erosion hazard, that preclude cultivation. It has moderate limitations for trafficways, campsites, and picnic areas, and severe limitations for resi- dences, buildings for light industry, intensive play areas, and golf fairways. (Capability unit VIs-3; woodland group 4; Shallow range sites 3, 6, and 9, precipitation zones 45 to 60 inches, 35 to 45 inches, and 25 to 35 inches) Descalabrado clay loam, 20 to 40 percent slopes (DeE).--This soil is on side slopes of dissected up- lands (pl. I) in the western and northern parts of St. Croix. Included in mapping were spots of Cramer gravelly clay loam and Victory clay loam on the steeper slopes, spots of Jacana clay loam and San Anton clay loam along the drains and on the lower foot slopes, and very small areas of Volcanic rock land. This Descalabrado soil has the profile described as representative for the series. The surface layer is 4 to 7 inches thick. The depth to hard rock ranges from 10 to 20 inches. This soil is suited to pasture and woodland. Most of the acreage is in grasses and is used as pasture. Steep slopes, shallowness over rock, the erosion hazard, and a low water-holding capacity preclude cultivation. The limitation is severe for most nonfarm uses, as for residences, buildings for light industry, trafficways, campsites, picnic areas, intensive play areas, and golf fairways. (Capability unit VIs-3; woodland group 4; Shallow range sites 3, 6, and 9, precipitation zones 45 to 60 inches, 35 to 45 inches, and 25 to 35 inches) Descalabrado clay loam, 40 to 60 percent slopes (DeF) .--This soil is on side slopes of dissected volcanic uplands, mainly in the northern and north- western parts of St. Croix. Included in mapping were small areas of Cramer gravelly clay loam and Southgate clay loam, narrow bands of San Anton clay loam along the drains, areas where the underlying volcanic rock contains secondary lime, and areas of Volcanic rock land, The surface layer of this Descalabrado soil is 3 to 5 inches thick. The depth to rock ranges from 10 to 18 inches. This soil is too steep and too shallow to be suited to cultivated crops. It can be used for pas- ture and woodland. Limitations are severe for resi- dences, buildings for light industry, trafficways, campsites, picnic areas, intensive play areas, and golf fairways. (Capability unit VIIs-3; woodland group 4; Shallow range sites 3, 6, and 9, precipita- tion zones 45 to 60 inches, 35 to 45 inches, and 25 to 35 inches) Diamond Series The Diamond series consists of nearly level to moderately sloping, well-drained soils that are shal- low over semiconsolidated limestone. These soils 14 formed in sediments derived from limestone. They occur near coastal areas in the southern and south- western parts of St. Croix. The slope gradient is 0 to 12 percent. The climate is semiarid. The average annual rainfall is between 30 and 35 inches, and the average annual temperature is between 78° and 80° F. In a typical profile the surface layer is dusky- red clay loam about 2 inches thick. The subsoil is dark reddish-brown, friable clay loam that is about 15 percent limestone fragments. Below this is dark- red, friable, calcareous loam, Hard limestone is at a depth of about 14 inches. The Diamond soils in this survey area were mapped with Limestone rock land. Most of the acreage is in grasses and shrubs and is used as pasture and build- ing sites. Representative profile of. Diamond clay loam, 0 to 5 percent slopes, on the southwestern tip of St. Croix, near White Ladys, east of Westend Saltpond: Al~-0 to 2 inches, dusky-red (2.5YR 3/2) clay loam; weak, fine, granular structure; very friable, slightly sticky; abrupt, smooth boundary. 2 to 5 inches thick. B2--2 to 10 inches, dark reddish-brown (2.5YR 3/4) clay loam; moderate, coarse, granular struc- ture; friable, slightly sticky, plastic; about 15 percent limestone fragments; common roots; mildly alkaline; clear, wavy boundary. 4 to 10 inches thick. C--10 to 14 inches, dark-red (2.5YR 3/6) heavy loam; massive; friable, slightly sticky, nonplas- tic; few roots; calcareous; moderately alka- line; abrupt, irregular boundary. 2 to 5 inches thick. R--14 inches +, semiconsolidated limestone. The depth to limestone ranges from 8 to 16 inches. There are few to many limestone fragments throughout the profile. The reaction ranges from neutral to moderately alkaline. The color of the A horizon ranges from 5YR to 2.5YR in hue, 2 to 3 in value, and 2 to 3 in chroma. The texture of the A horizon is dominantly clay loam. The color of the B horizon ranges from dark reddish brown (2.5YR 3/4) to dark red (2.5YR 3/6). The texture is dominantly clay loam, The structure of the B2 horizon ranges from moderate, coarse, granular to moderate, fine, subangular blocky. ; Diamond soils are associated with Hesselberg, Aguilita, Sion, and Fredensborg soils. They are shallower, less clayey, and redder than Hesselberg soils. They differ from Aguilita, Sion, and Fre- densborg soils in that those soils are underlain by soft marl. They are redder and slightly deeper than Aguilita soils. They are redder and slightly shal- lower than Sion soils. They are redder, less clay- ey, and less calcareous than Fredensborg soils. ‘Diamond-Limestone rock land complex, 0 to 5 per- cent slopes (D1B).--This complex occurs as small, irregularly shaped, undulating areas. Diamond clay loam makes up 50 to 70 percent of each mapped area. Included in mapping were spots of Hesselberg clay and Fredensborg clay. The Diamond soil in this complex has the profile described as representative for the series. Lime- stone rock land is described under the heading "Limestone rock land." This complex is ‘suited to pasture and woodland. Shallowness and rock outcrops preclude cultivation and severely limit use of this complex for resi- dences, buildings for light industry, trafficways, campsites, picnic areas, intensive play areas, and golf fairways. (Capability unit VIs-2; woodland group 2; Rough Stony Land range site 10, all pre- cipitation zones) Diamond-Limestone rock land complex, 5 to 12 per- cent slopes, eroded (@1C2).--This complex is on ridges and knolls. Diamond clay loam makes up 50 to 70 percent of each mapped area. Included in mapping were spots of Aguilita clay loam. The Limestone rock land part of this complex con- sists of semiconsolidated limestone, softer than that of Diamond-Limestone rock land, 0 to 5 percent slopes. The fractured limestone has been mixed with the soil material through erosion and deep tillage. Thus, the Diamond soil in this complex is more grav- elly than that in the Diamond-Limestone rock land complex previously described. This complex is suited to pasture and woodland. Shallowness and rock outcrops preclude cultivation. Shallowness over limestone limits use of this com- plex for residences, buildings for light industry, and trafficways, but because of the softer nature of the limestone, the limitation is only moderate. Rockiness is a severe limitation for recreational purposes, as for campsites, picnic areas, intensive play areas, and golf fairways. (Capability unit VIs-2; woodland group 2; Rough Stony Land range site 10, all precipitation zones) Dorothea Series The Dorothea series consists of moderately steep to steep, deep, well-drained soils over highly weath- ered, basic volcanic rocks mixed with unweathered volcanic boulders. These soils formed in material derived from these rocks. They occur on dissected volcanic uplands, mainly on the northern coast of St. Thomas. The slope gradient is 20 to 60 percent. The climate is tropical semiarid. The average an- nual rainfall is between 40 and 55 inches, and the average annual temperature is between 78° and 80° F. In a typical profile the surface layer is dark- brown clay loam about 6 inches thick. The subsoil is yellowish-brown, very firm clay to a depth of about 19 inches. Below this is strong-brown, fri- able clay loam. At a depth of about 30 inches is highly decomposed volcanic rock mixed with hard volcanic boulders. Most of the acreage is used for cultivated crops or pasture. Part of it is being subdivided for housing developments. Representative profile of Dorothea clay loam, 20 to 40 percent slopes, on St. Thomas, 1,000 feet west 382-314 O- 70-2 of Lilliendahl junction, which is 1,000 yards east of the Dorothea Experiment Station and 75 feet south of the road: Al--0 to 6 inches, dark-brown (10YR 4/3) clay loam; weak, fine and medium, subangular blocky structure that breaks to moderate, medium, granular; friable, nonsticky, slightly plas- tic; many roots; slightly acid; clear, smooth boundary. 4 to 8 inches thick. B21t--6 to 11 inches, yellowish-brown (10YR 5/6) clay; moderate, medium, subangular blocky structure; very firm, slightly sticky, plas- tic; thin, discontinuous, dark-brown (10YR 4/3) coatings on vertical and horizontal peds; few small pressure faces; common roots; few worm casts; slightly acid; clear, smooth boundary. 4 to 7 inches thick. B22t--11 to 19 inches, yellowish-brown (10YR 5/6) clay; moderate, medium and coarse, subangular blocky structure; very firm, slightly sticky, plastic; thin, discontinuous, brown (10YR 4/3) coatings; few small pressure faces; few roots; few worm casts; slightly acid; clear, smooth boundary. 6 to 10 inches thick. B3--19 to 30 inches, strong-brown (7.5YR 5/6) clay loam; weak, medium and coarse, subangular blocky structure; friable, slightly sticky, slightly plastic; thin, patchy, dark yellow- ish-brown (10YR 4/4) clay films; few roots; few black nodules; 25 to 35 percent sapro- lite; slightly acid; gradual, smooth bound- ary. 9 to 12 inches thick. C--30 to 36 inches +, highly weathered, basic vol- canic extrusive rock (saprolite) mixed with a few large, unweathered volcanic boulders. The thickness of the solum ranges from 24 to 37 inches. The reaction ranges from medium acid to neutral. The texture is mainly clay loam. In spots it is silty clay loam. The color of the A horizon is 10YR and 7.5YR in hue, 4 in value, and 2 to 4 in chroma. The texture of the B2t horizon ranges from heavy clay loam to silty clay and clay. The color ranges from yellowish brown (10YR 5/4, 5/6, 5/8) to strong brown (7.5YR 5/6, 5/8). The structure of these horizons ranges from moderate, medium, suban- gular blocky to moderate, coarse, subangular blocky. There are thin discontinuous clay films. The per- centage of saprolite in the B3 horizon ranges from 20 to 40. Laboratory determinations show high base saturation (80 percent) and a Ca/Mg ratio of 1:1 in the B2t horizon. Dorothea soils are associated with Cramer, Isaac, Victory, and Magens soils. They are deeper over volcanic rock and are less red than Cramer soils. They are shallower over volcanic rock and are less red than Isaac soils. They are deeper over rock and have a more strongly developed subsoil than Victory soils. They are not so red nor so acid as Magens soils, and their underlying material is not so highly decomposed. Dorothea clay loam, 20 to 40 percent slopes (DoE) .--This soil is on side slopes of dissected 15 volcanic uplands on the northern coast of St. Thomas. Included in mapping, and making up less than 15 per- cent of each mapped area, were spots of Victory, Magens, and Cramer soils. This Dorothea soil has the profile described as representative for the series. The surface layer is 4 to 8 inches thick. The depth to weathered rock is 28 to 37 inches. This soil is suited to pasture and woodland. The slope and the erosion hazard preclude cultivation. Truck crops can be grown if rock barriers are estab- lished (pl. I}. Slope severely limits use of this soil for residences, buildings for light industry, trafficways, campsites, picnic areas, intensive play areas, or golf fairways. (Capability unit VIe-1; woodland group 1; Hilly Clay range sites 2 and S, precipitation zones 45 to 60 inches and 35 to 45 inches) Dorothea clay loam, 40 to 60 percent slopes (DoF).--This soil is on side slopes of dissected volcanic uplands on the northern coast of St. Thomas. Included in mapping, and making up 10 to 15 percent of each mapped area, were spots of Victory, Magens, and Cramer soils. The surface layer of this Dorothea soil is 4 to 7 inches thick. The depth to weathered rock is 24 to 37 inches. This soil is suited to pasture and woodland. Establishing and maintaining grasses is more diffi- cult than on Dorothea clay loam, 20 to 40 percent slopes. The slope and the erosion hazard preclude cultivation. The slope is a severe limitation for nonfarm purposes, as for residences, buildings for light industry, trafficways, campsites, picnic areas, intensive play areas, or golf fairways. (Ca- pability unit VIIe-2; woodland group 1; Hilly Clay range sites 2 and 5, precipitation zones 45 to 60 inches and 35 to 45 inches) Fraternidad Series The Fraternidad series consists of deep, nearly level to moderately sloping, moderately well drained soils that formed in clayey sediments derived from volcanic and limestone hills. These soils occur near coastal areas in the southern part of St. Croix. The slope gradient is 0 to 12 percent. The climate is semiarid. The average annual rainfall is between 30 and 45 inches, and the average annual temperature is between 78° and 80° F. In a typical profile the surface layer is very dark grayish-brown and dark grayish-brown clay about 13 inches thick. Below this, to a depth of about 62 inches, is light olive-brown, calcareous, very firm clay. Drainage is moderately good. Permeability is slow. Most of the acreage is cultivated. A small acreage is in grass and is used for pasture. Representative profile of Fraternidad clay, 0 to 3 percent slopes, on St. Croix, three-tenths of a mile west on the farm road along the north side of Lower Love and 400 feet north: Ap--0 to 6 inches, very dark grayish-brown (2.5Y 3/2) clay; moderate, medium, granular struc- 16 ture; friable, sticky, plastic; common roots; strongly effervescent; clear, smooth boundary. Al--6 to 13 inches, dark grayish-brown (2.5Y 4/2) clay; weak, fine and medium, subangular blocky structure (few small angular peds); very firm, sticky, plastic; few, fine, angular volcanic rock fragments; few, fine, black nodules; few worm casts 1 to 2 millime- ters in diameter; strongly effervescent; clear, wavy boundary. 4 to 12 inches thick. A3--13 to 23 inches, light olive-brown (2.5Y 5/4) clay; weak, medium, subangular blocky struc- ture with rhombic form and pressure faces; very firm, sticky, plastic; few angular volcanic fragments; few, fine, black nodules less than 2 millimeters in diameter; very few roots; strongly effervescent; clear, wavy boundary. 6 to 16 inches thick. C1--23 to 31 inches, light olive-brown (2.5Y 5/4) clay; medium to coarse, intersecting, angular or wedge-shaped peds and numerous slicken- sides and pressure faces; very firm, sticky, plastic; few fine limestone fragments; few angular volcanic fragments; few, fine, black nodules; strongly effervescent; small blotch- es of secondary lime; clear, wavy boundary. 6 to 10 inches thick, C2--31 to 43 inches, light olive-brown (2.5Y 5/4) clay; medium to coarse, intersecting, angular or wedge-shaped peds and numerous slicken- sides and pressure faces; very firm, sticky, and plastic; few fine limestone fragments; strongly effervescent; clear, wavy boundary. 8 to 14 inches thick. C3ca--43 to 62 inches, light olive-brown (2.5Y 5/4) clay; common, medium, distinct, yellowish- brown (10YR 5/6) mottles; medium and coarse, angular and wedge-shaped peds and pressure faces and slickensides (less numerous than in C2 horizon); very firm, sticky, and plastic; few black nodules 1 millimeter in diameter; few limestone concretions; violently effer- vescent; numerous blotches of secondary lime; abrupt, wavy boundary. 10 to 22 inches thick. IIB21b--62 to 76 inches, strong-brown (7.5YR 5/8) with seams of black (5Y 2/2) gravelly clay loam; very weak, subangular blocky structure; thin patchy clay films; firm, slightly plas- tic; few angular volcanic fragments; few black nodules 1 to 2 millimeters in diameter; slightly effervescent; clear, wavy boundary. 8 to 16 inches thick. IIIB22tb--76 to 78 inches, strong-brown (7.5YR 5/8) clay loam; weak, medium, subangular blocky structure; thin, olive (SY 3/3), discontinu- ous clay films, friable, nonsticky, and plas- tic; few black nodules; matrix noncalcareous; very few limestone blotches. Limestone and volcanic fragments range from few to many and are scattered throughout the profile. The depth to gravelly sediments or marl ranges from 48 to 72 inches. The color of the A horizon ranges from very dark brown (10YR 2/2) to brown (10YR 4/3) and very dark grayish brown (2.5Y 3/2) to dark gray- ish brown (2.5Y 4/2}. The A horizon is massive when wet. The structure is either granular or fine sub- angular blocky when dry. The color of the C horizon ranges from brown (10YR 4/3) to yellowish brown (10YR 5/6} and dark grayish brown (2.5Y 4/2) to light olive brown (2.5Y 5/4). The C horizon has few to many wedge-shaped peds and slickensides that range from 1 to 8 inches in diameter. The peds in- tersect, and the faces are commonly oriented approxi- mately 60° from the surface. There are few to many peds or pockets of soil material from one horizon in adjoining horizons because of the churning action of the soil. The depth to strongly calcareous material ranges from 0 to 20 inches. Fraternidad soils are associated with Aguirre, Coamo, Fredensborg, and Glynn soils. They are bet- ter drained and have a lighter colored profile than Aguirre soils. They are less friable, more clayey, and more poorly drained than Coamo soils. They are more poorly drained than Fredensborg soils, which are shallow over soft marl. They are more clayey and less brown than Glynn soils, which have a well- developed subsoil. Fraternidad clay, 0 to 3 percent slopes (FcA).-- This soil is in the southern ‘and southwestern parts of St. Croix. A large area occurs near Lower Love. Included in mapping, and making up 5 to 15 percent of each mapped area, were spots of Coamo clay loam, Glynn clay loam in areas where sediments from vol- canic rocks are dominant, Aguirre clay in depres- sional concave areas, and Fredensborg clay where this Fraternidad soil is near areas of soft lime- stone or marl. This Fraternidad soil has the profile described as representative for the series. Slow percolation, slow permeability, plastic and sticky consistence, and poor workability limit use of this soil for farming. Climate also is an ad- verse factor. Nevertheless, a large part of.the acreage is in cultivated crops. Pasture grasses do well. Limitations are severe for trafficways, resi- dences, buildings for light industry, campsites, picnic areas, intensive play areas, and golf fair- ways. (Capability unit IIIs-1; no woodland classi- fication; Deep range site 4, precipitation zone 35 to 45 inches) Fraternidad clay, 3 to 12 percent slopes, eroded (FcC2).--This soil occurs along small drainageways and on foot slopes in the southern and southwestern parts of St. Croix. Included in mapping were spots of Jacana and Descalabrado soils. Erosion has removed much of the original granular surface layer from this Fraternidad soil. The pres- ent surface layer is only 4 to 6 inches thick. In spots the lighter colored, more plastic underlying material is exposed. This soil takes in water slowly, expands when wet and shrinks when dry, and is difficult to till. If tilled, it is.subject to further erosion. Limita- tions are severe for trafficways, residences, buildings for light industry, campsites, picnic areas, intensive play areas, and golf fairways. (Capability unit IVe-2; no woodland classification; Deep range site 4, precipitation zone 35 to 45 inches) Fredensborg Series The Fredensborg series consists of nearly level to moderately sloping, well-drained soils that formed in clayey, calcareous sediments over soft limestone or marl. These soils occur near coastal areas on St. Croix, in valleys and on foot slopes below the limestone hills. The slope gradient is 0 to 12 percent. The climate is semiarid. The average annual rainfall is between 35 and 40 inches, and the average annual temperature is between 78° and 80° F, In a typical profile the surface layer is very dark grayish-brown, calcareous clay about 16 inches thick. The next layer is very pale brown, very friable, calcareous silty clay loam. At a depth of about 20 inches is very pale brown, soft marl or limestone. These soils are used for crops and pasture, main- ly row crops and guineagrass. Representative profile of Fredensborg clay, 2 to 5 percent slopes, on St. Croix, 150 feet west and 75 feet north of an intersection a quarter of a mile west of .Kingshill: Ap--0 to 10 inches, very dark grayish-brown (10YR 3/2) clay; weak, medium, subangular blocky structure that breaks to moderate, fine, granular; hard, firm, slightly sticky, plas- tic; many small pressure faces; calcareous; many small shell and limestone fragments; moderately alkaline; clear, smooth boundary. 6 to 10 inches thick, Al--10 to 16 inches, very dark grayish-brown (10YR 3/2) clay; moderate, fine, granular struc- ture; hard, firm, slightly sticky, plastic; many light-colored worm casts; calcareous; many small shell and limestone fragments; moderately alkaline, abrupt, smooth boundary. 2 to 10 inches thick. AC--16 to 20 inches, very pale brown (10YR 7/3) silty clay loam; very weak, fine and medium, granular structure; very friable, soft, non- sticky, slightly plastic; many worm casts filled with dark-colored material; calcare- ous; strongly alkaline; clear, smooth bound- ary. 2 to 8 inches thick. C1--20 to 36 inches, very pale brown (10YR 7/3), silty, soft marl or limestone and a few small, soft lime concretions. 10 to 20 inches thick. C2--36 to 50 inches, pale-brown (10YR 6/3), silty, soft marl or limestone and many small, soft lime concretions. Material is easily pene- trated with a spade or an auger. The thickness of the solum ranges from 10 to 20 inches. Few to common limestone fragments are 17 scattered throughout the profile. The color of the A horizon is dominantly 10YR in hue, 2 to 3 in value, and 2 to 4 in chroma. The structure ranges from weak, medium, subangular blocky to weak and moderate granular. The AC horizon is a mixture of material from the A horizon and the underlying soft limestone. This mixture is the result of worm activity. Fredensborg soils are associated with Sion, Hes- selberg, Aguilita, Fraternidad, Coamo, and Pozo Blanco soils. They are more clayey than Sion soils. They are less friable and less red than Hesselberg soils, which have a moderately well developed sub- soil and are underlain by hard limestone. They are deeper and more clayey than Aguilita soils. They are shallower and less sticky than Fraternidad soils, in which the underlying material is strati- fied with sand and gravel. They are shallower and more clayey than Coamo soils. They are more clayey than Pozo Blanco soils, which have a weakly devel- oped subsoil. Fredensborg clay, 0 to 2 percent slopes (FrA).-- This soil is on St. Croix, in valleys between the limestone hills. Included in mapping were spots of Fraternidad clay and, in the southern and eastern parts of the island, spots of Sion clay loam. The surface layer of this Fredensborg soil is very dark brown to very dark grayish brown and is 7 to 10 inches thick. ‘The depth to soft limestone or marl is 12 to 20 inches. Moderately slow permeability and less than opti- mum workability are slight limitations for all farm uses. There is no erosion hazard. The plastic surface layer is a moderate limitation for use of this soil for residences, buildings for light in- dustry, trafficways, and golf fairways, and a severe limitation for campsites, picnic areas, and inten- sive play areas. (Capability unit IIs-1; woodland group 2; Deep range site 4, precipitation zone 35 to 45 inches) Fredensborg clay, 2 to 5 percent slopes (FrB).-- This soil is in the southern and southwestern parts of St. Croix. Included in mapping were spots of Sion clay loam and, in undulating areas, spots of Fredensborg clay, 0 to 2 percent slopes. This Fredensborg soil has the profile described as representative for the series. This soil is suited to cultivated crops, pasture grasses, and trees. Much of the acreage is in row crops (pl. II). The plastic and sticky nature of the clay when wet and the resulting poor worka- bility are moderate limitations for all farm uses. The erosion hazard is moderate. This soil has a moderate limitation for residences, buildings for light industry, trafficways, and golf fairways, and a severe limitation for campsites, picnic areas, and intensive play areas. (Capability unit IIIs-2; woodland group 2; Deep range site 4, precipitation zone 35 to 45 inches) Fredensborg clay, 5 to 12 percent slopes, eroded (FrC2).--This soil is in the southern and southwest- ern parts of St. Croix, on foot slopes below the 18 limestone hills. Included in mapping were small areas of Aguilita gravelly clay loam. The surface layer of this Fredensborg soil is 6 to 8 inches thick. The depth to soft limestone or marl is 10 to 18 inches. . The plastic and sticky nature of the clay when wet and the resulting poor workability limit the use of this soil for farming. The erosion hazard is se- vere. This soil has a moderate limitation for residences, buildings for light industry, and golf fairways, and a severe limitation for campsites, picnic areas, intensive play areas, and trafficways. (Capability unit IVe-4; woodland group 2; Deep range site 4, precipitation zone 35 to 45 inches) Glynn Series The Glynn series consists of deep, gently slop- ing to moderately sloping, well-drained soils that formed in clay loam and clayey sediments over strat- ified sandy loam, clay loam, and clay. These soils are on alluvial fans. The slope is convex, and the gradient is 2 to 12 percent. The climate is semi- arid, The average annual rainfall is between 35 and 40 inches, and the average annual temperature is between-78° and 80° F. In a typical profile the surface layer is dark- brown clay loam about 12 inches thick. The upper part of the subsoil is dark yellowish-brown, firm clay. The lower part is dark yellowish-brown and yellowish-brown, friable and very friable clay loam. The underlying material, at a depth of about 50 inches, is yellowish-red and strong-brown, strati- fied sandy loam, clay loam, and clay. Some areas are in row crops and guineagrass, some are in native grasses and shrubs, and others are used as building sites. Representative profile of Glynn clay loam, 2 to 5 percent slopes, on St. Croix, one-eighth: of a mile south and 150 feet west of Grove Place, which is approximately one-tenth of a mile north of St. Lukes Church: Al--0 to 12 inches, dark-brown (10YR 3/3) clay loam, light brownish gray (10YR 6/2) when dry; mod- erate, medium, granular structure; very hard, firm, slightly sticky, slightly plastic; few subrounded fragments of volcanic rock; neu- tral; clear, smooth boundary. 8 to 15 inches thick. B2t--12 to 23 inches, dark yellowish-brown (10YR 4/4) clay; moderate, medium, prismatic struc- ture that breaks to moderate, fine and medi- um, subangular blocky; very hard, firn, slightly sticky, slightly plastic; thin, patchy, brown (10YR 4/3) clay films on verti- cal and horizontal ped surfaces; common, fine, subrounded volcanic fragments; many worm casts; many roots; mildly alkaline; clear, smooth boundary. 10 to 18 inches thick. B31--23 to 30 inches, dark yellowish-brown (10YR 4/4) clay loam; weak, medium, subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; few, thin, patchy clay films on vertical ped surfaces; few subrounded fragments of volcanic rock; mildly alkaline; clear, smooth boundary. 6 to 16 inches thick. IIB32--30 to 50 inches, yellowish-brown (10YR 5/6) clay loam; weak, coarse, subangular blocky structure; very friable, slightly sticky, nonplastic; few patchy clay films; few, fine, rounded volcanic fragments; mildly alkaline; clear, smooth boundary. 10 to 20 inches thick. IIIC--50 inches +, yellowish-red (5YR 5/8) and strong-brown (7.5YR 5/8), stratified sandy loam, clay loam, and clay; pockets and lenses of secondary lime; small to large amount of gravel; few patchy clay films and clay-coated sand grains. The depth to the IIB horizon ranges from 30 to 49 inches. Gravel occurs throughout the profile. The depth to the IIIC horizon ranges from 48 to 60 inches. The color of the A horizon is dark brown (10YR 3/3). ‘The texture is dominantly clay loam but ranges to loam. The color of the B2t horizon ranges from 10YR to SYR in hue, and from 3 to 4 in chroma and value. The texture is dominantly clay but ranges to clay loam. The structure of the B2t hori- zon ranges from moderate, medium, prismatic to strong, medium, subangular blocky. The color of the B3 horizon ranges from dark yellowish brown (10YR 4/4) to yellowish brown (10YR 5/4). The texture ranges from clay to clay loam. The underlying finer textured layer that has weak structure and patchy clay films is a buried B horizon. Below the B3 horizon is stratified sandy loam, clay loam, -and clay and varying amounts of gravel. Any or all of these layers may contain secondary lime. Glynn soils are associated with Isaac, Parasol, Lavallee, Coamo, Fraternidad, San Anton, and Jacana soils. They are deeper over rock and are less red than Isaac soils. They are less friable, are light- er colored, and have a slightly thinner surface lay- er than Parasol soils. They are deeper and are less gravelly than Lavallee soils. They have a less fri- able surface layer and have brighter colors in the subsoil than Coamo soils. They are less clayey, less plastic, and better drained than Fraternidad soils. They have a more strongly developed subsoil than San Anton soils, which formed in more recent sediments along the inland streams. They are deeper and have a more strongly developed subsoil than Jacana soils, which occupy positions just above Glynn soils, on lower foot slopes of the volcanic uplands. Glynn clay loam, 2 to 5 percent slopes (GyB) .-- This soil occurs as fairly large areas on foot slopes and alluvial fans in the western half of St. Croix and'as small areas throughout the other is- lands. Included in mapping were narrow bands of San Anton clay loam, and small areas of Coamo clay loam. This Glynn soil has the profile described as rep- resentative for the series. This soil has only a slight erosion hazard and a slight limitation for most farm uses. Its surface layer is friable when moist but becomes hard and difficult to dig into when dry. It has a slight limitation for trafficways, golf fairways, and buildings for light industry, and a moderate limitation for residences, campsites, picnic areas, and intensive play areas. (Capability unit IIe-2; woodland group 3; Deep range sites 1, 4, and 7, precipitation zones 45 to 60 inches, 35 to 45 inches, and 25 to 35 inches) Glynn clay loam, 5 to 12 percent_slopes, eroded (GyC2).--This soil is mainly in the western part of St. Croix, on alluvial fans and breaks along upland drains. Included in mapping were spots of San Anton clay loam and Coamo clay loam. Erosion has removed much of the original surface layer of this Glynn soil, and the present surface layer is only 8 to 10 inches thick. The depth to the underlying material (IIB horizon) is 30 to 40 inches. This soil is friable when moist but becomes hard and difficult to dig into when dry. Because of the slope and the erosion hazard, it is moderately lim- ited for all farm uses. It has little or no limita- tion for picnic areas and trafficways. The slope and the slow percolation rate are moderate limita- tions for residences, buildings for light industry, campsites, and golf fairways. The slope severely limits its use for intensive play areas. (Capabil- ity unit IIIe-1; woodland group 3; Deep range sites 1, 4, and 7, precipitation zones 45 to 60 inches, 35 to 45 inches, and 25 to 35 inches) Hesselberg Series The Hesselberg series consists of nearly level to gently undulating, well-drained soils that are shal- low over hard limestone. These soils formed in clayey material weathered in place from limestone. They occur near coastal areas in the’ southern and southwestern parts of St. Croix. The slope gradient is 0 to 2 percent. The climate is semiarid. The average annual rainfall is between 30 and 40 inches, and the average annual temperature is between 78° and 80° F. In a typical profile the surface layer is dark reddish-brown, calcareous clay about 7 inches thick. The upper part of the subsoil is dark reddish-brown, friable, calcareous clay. The lower part is dark- red, friable, calcareous clay. Hard, white lime- stone is at a depth of about 18 inches. The acreage is about equally divided between range and cropland. Range vegetation consists of guineagrass, native grasses, and shrubs. Cultivated areas are mainly in row crops. Representative profile of Hesselberg clay, 0 to 2 percent slopes, on St. Croix, seven-tenths of a mile west of the south entrance to the airport, 400 feet south on a secondary road, and 50 feet west of the road: Ap--0 to 7 inches, dark reddish-brown (SYR 3/3) clay; moderate, medium, subangular blocky 19 structure; slightly hard, friable, slightly sticky, slightly plastic; many roots; few limestone fragments; calcareous; mildly alka- line; clear, smooth boundary. 4 to 8 inches thick. Bl--7 to 12 inches, dark reddish-brown (SYR 3/3) clay; moderate, fine, subangular blocky structure; friable, slightly sticky, plastic; many fine roots; calcareous; few limestone fragments; mildly alkaline; clear, smooth boundary. 4 to 6 inches thick. — to 17 inches, dark-red (2.5YR 3/6) clay; weak, medium, prismatic structure that breaks to moderate, fine and medium, subangular blocky; friable, slightly sticky, plastic; common fine roots; few limestone fragments; few dark reddish-brown (5YR 3/3) worm casts; calcare- ous; mycelial lime; mildly alkaline; abrupt, wavy boundary. 2 to 6 inches thick. Clcam--17 to 18 inches, hard white limestone; light- red (2.5YR 6/6) lamins. C2cam--18 to 24 inches +, white, partly silicified limestone. B2--12 The depth to silicified limestone ranges from 10 to 20 inches but is dominantly 16 to 20 inches. The profile is weakly to strongly calcareous and has few to common limestone fragments throughout. The color of the A horizon ranges from 7.5YR to S5YR in hue and from 2 to 3 in chroma and value. The texture is dominantly clay but ranges to silty clay. The color of the B horizon ranges from SYR to 2.5YR in hue, 3 to 6 in chroma, and 3 to 4 in value. The texture ranges from silty clay to clay. The structure of the B horizon ranges from moderate, fine, subangular blocky to weak, medium, prismatic and moderate, fine and medium, subangular blocky. There are few to no visible clay films. Hesselberg soils are associated with Diamond, Fredensborg, Sion, and Aguilita soils. They are more clayey and more strongly developed than Diamond soils. They are not so brown as Fredensborg and Sion soils, both of which are underlain by soft limestone. They are deeper than Aguilita soils, which are gravelly, are very dark grayish brown, and overlie soft limestone. Hesselberg clay, 0 to 2 percent slopes (HeA).-- This soil is in the southern and southwestern parts of St. Croix. Included in mapping were small areas of Diamond clay loam. This soil is used for cultivated crops, mainly row crops, and for grassland. Shallowness over rock, a small amount of available water for plants, and adverse climate are limitations for all farm uses. The limitation is moderate for golf fairways and trafficways, and severe for residences, build- ings for light industry, campsites, picnic areas, and intensive play areas. (Capability unit IIIsc-1l; no woodland classification; Shallow range site 6, precipitation zone 35 to 45 inches) Isaac Series The Isaac series consists of moderately sloping to steep, acid, well-drained soils that are moder- ately deep over basic volcanic rocks. These soils 20 formed in material derived in place from these rocks. They occur throughout the islands, on side slopes and foot slopes of dissected volcanic up- lands. The slope gradient is 5 to 40 percent. The climate is semiarid. The average annual rainfall is between 35 and 55 inches, and the average annual temperature is between 78° and 80° F. In a typical profile the surface layer is dark reddish-brown gravelly clay loam about 8 inches thick. The uppermost part of the subsoil is dark reddish-brown, friable gravelly clay loam about 3 inches thick. The middle part is red, firm clay. The lowermost part is yellowish-red, friable clay loam. At a depth of about 24 inches is yellowish- red, very friable clay loam. This material, about 12 inches thick, is decomposed volcanic rock. Below this is bedded volcanic rock. Most areas are in brush or brushy forest. Some are subdivided for housing developments. Very few are used for pasture or cultivated crops. Representative profile of Isaac gravelly clay loam, 5 to 20 percent slopes, 1,000 feet northeast of St. Croix Beach Hotel: Ap--0 to 8 inches, dark reddish-brown (5YR 3/3) gravelly clay loam; weak, fine, granular structure; friable, slightly sticky, slightly plastic; many fine roots; about 30 percent hard angular volcanic gravel; slightly acid; clear, smooth boundary. 6 to 14 inches thick. Bl--8 to 11 inches, dark reddish-brown (5YR 3/4) gravelly heavy clay loam; weak, fine, suban- gular blocky structure; friable, slightly sticky, slightly plastic; common fine roots; about 30 percent hard volcanic gravel; slightly acid; clear, smooth boundary. 6 inches thick. B2t--11 to 19 inches, red (2.5YR 4/6} clay; moder- ate, medium, subangular blocky structure; firm, slightly sticky, plastic; few, fine, angular volcanic fragments; thin patchy clay films on ped surfaces; few fine roots; neu- tral; gradual, smooth boundary. 6 to 10 inches thick. to 24 inches, yellowish-red (5YR 4/6) clay loam; weak, medium, subangular blocky struc- ture; friable, slightly sticky, slightly plastic; common fine and medium volcanic fragments; very few patchy clay films on ped surfaces; very few fine roots; neutral; grad- ual, smooth boundary. 3 to 7 inches thick. C--24 to 36 inches, yellowish-red (SYR 4/6) light clay loam; massive; very friable, nonsticky, slightly plastic; original rock structure is visible; neutral; clear, smooth boundary. 8 to 14 inches thick. R--36 inches +, semiconsolidated, bedded, extrusive volcanic rock. 3 to B3--19 The thickness of the solum ranges from 18 to 33 inches. The depth to hard rock ranges from 20 to 72 inches or more. The reaction ranges from medium acid to neutral (pH 5.5 to 7.3). The texture of the A horizon ranges from clay loam to gravelly clay loam. Gravel makes up 5 to 50 percent of the soil mass. The color of the A horizon ranges from very dark brown (10YR 2/2) and dark brown (7.5YR 3/2) to dark reddish brown (5YR 3/4). The B2t horizon is dominantly clay. The color ranges from 5YR to 2.5YR in hue, 3 to 4 in value, and 4 to 8 in chroma. The structure of the B2t horizon ranges from weak, me- dium, subangular blocky to moderate, coarse, sub- angular blocky. Strong vertical cleavage and pres- sure faces are evident when the soil is dry. Isaac soils are associated with Coamo, Parasol, Cramer, Dorothea, and Victory soils. They are not so brown as Coamo soils, which have a layer of accu- mulated calcium carbonate within a depth of 40 inch- es and stratified, gravelly underlying material. They are not so brown as Parasol soils, which are underlain by highly decomposed and fractured grani- tic rock. They have a darker colored surface layer and are redder than Dorothea soils. They are less yellow and have a more strongly developed subsoil than Victory soils. Isaac clay loam, saprolitic substratum, 12 to 20 percent slopes, eroded (IsD2).--This soil is on side slopes and foot slopes of dissected volcanic uplands on the islands of St. Thomas and St. John. Included in mapping were small areas of Dorothea clay loam, Cramer gravelly clay loam, and Victory clay loam. This Isaac soil has a slightly thinner surface layer, a slightly thicker subsoil, and looser, more decomposed underlying material than the soil de- scribed as representative for the series. The pres- ent surface layer is 6 to 8 inches thick, The un- derlying rock can be excavated easily with a spade. This soil is suited to pasture or woodland. The entire acreage is in brushy forest. The strong slopes and the erosion hazard preclude cultivation. The limitation is moderate for picnic areas, camp- sites, and trafficways, and severe for residences, buildings for light industry, intensive play areas, and golf fairways. (Capability unit VIe-1; woodland group 1; Hilly Clay range sites 2, 5, and 8, pre- cipitation zones 45 to 60 inches, 35 to 45 inches, and 25 to 35 inches) Isaac clay loam, saprolitic substratum, 20 to 40 percent slopes (IsE).--This soil is on side slopes of dissected volcanic uplands on the islands of St. Thomas and St. John. Included in mapping were spots where the surface layer is gravelly and spots of Cramer, Victory, and Dorothea soils. This Isaac soil has a dark-colored, granular sur- face layer 8 to 14 inches thick. Its subsoil is thicker than that in the profile described as repre- sentative for the series, and the underlying mate- rial is looser and more decomposed. This underlying material can be excavated easily with a spade. This soil is suited to pasture or woodland. The entire acreage is in brushy forest. The moderately steep slopes and the erosion hazard preclude culti- vation. The limitation is severe for nonfarm pur- poses, as for residences, buildings for light indus- try, trafficways, campsites, picnic areas, intensive play areas, and golf fairways. (Capability unit VIe-1; woodland group 1; Hilly Clay range sites 2, 5, and 8, precipitation zones 45 to 60 inches, 35 to 45 inches, and 25 to 35 inches) Isaac gravelly clay loam, 5 to 20 percent slopes (IvD) .--This soil occurs on side slopes and foot slopes of dissected volcanic uplands throughout the Virgin Islands. Included in mapping were spots of San Anton clay loam along the lower slopes near drains and spots of Cramer gravelly clay loam along the steeper slopes. This soil has the profile described as represent- ative for the series. The surface layer is 6 to 10 inches thick. The depth to decomposed volcanic rock is 18 to 33 inches. The depth to hard rock is 20 to 72 inches. This soil is suited to pasture or woodland. It has a moderately high water-holding capacity, but the slope, the erosion hazard, and the coarse frag- ments severely limit its use for cultivated crops. It has a moderate limitation for picnic areas, campsites, and trafficways, and a severe limita- tion for residences, buildings for light industry, intensive play areas, and golf fairways. (Capabil- ity unit VIe-1; woodland group 4; Hilly Clay range sites 2, 5, and 8, precipitation zones 45 to 60 inches, 35 to 45 inches, and 25 to 35 inches) Jacana Series The Jacana series consists of gently sloping to strongly sloping, well-drained soils that are moder- ately deep over basic volcanic rocks. These soils formed on clayey sediments in material derived in place from these rocks. They occur on foot slopes and low rolling hills, mainly on the island of St. Croix. The slope gradient is 2 to 20 percent. The average annual rainfall is between 30 and 45 inches, and the average annual temperature is between 78° and 80° F, In a typical profile the surface layer is very dark grayish-brown clay loam about 9 inches thick. The upper part of the subsoil is dark-brown, firm clay loam. The lower part is very dark grayish-brown and yellowish-brown, firm gravelly clay. This layer is a mixture of soil material and decomposed volcanic rock fragments. At a depth of about 26 inches is yellowish-brown, partly weathered volcanic rock. Below this, at a depth of about 29 inches, is hard fractured ‘rock. Generally these soils are used for pasture. A limited acreage is in cultivated crops, mainly row crops. Representative profile of Jacana clay loam, 2 to 5 percent slopes, on St. Croix, a little more than a tenth of a mile west of the headquarters’ building at Fountain on the Canady farm, or 140 feet east from the side drain and 350 feet north of the major west to east drain: Ap--0 to 9 inches, very dark grayish-brown (10YR 3/2) clay loam, dark grayish brown (10YR 4/2) when dry; weak, fine, subangular blocky structure; hard, friable, slightly sticky, plastic; common fine roots; common, fine, angular fragments of volcanic rock; neutral; 21 gradual, smooth boundary. 7 to 11 inches thick. B2--9 to 17 inches, dark-brown (10YR 3/3) heavy clay loam; weak, medium, subangular blocky struc- ture that breaks to moderate, fine, subangu- lar blocky; hard, firm, slightly sticky, plastic; 20 percent fine angular fragments of volcanic rock; common, fine, faint, very dark grayish-brown (10YR 3/2) krotovinas; few fine roots; neutral; gradual, smooth boundary. 6 to 10 inches thick. to 26 inches, mixed very dark grayish-brown (10YR 3/2) and yellowish-brown (10YR 5/4) gravelly clay; weak, coarse, subangular blocky structure that breaks to moderate, fine, subangular blocky; hard, firm, slightly sticky, slightly plastic; 50 percent weath- ered volcanic rock fragments; few fine roots; neutral; clear, wavy boundary. 7 to ll inches thick. C--26 to 29 inches, yellowish-brown (10YR 5/4), part- ly weathered volcanic rock; neutral; many volcanic rock fragments; abrupt, broken boundary. 0 to 6 inches thick. R--29 inches +, hard, fractured volcanic rock. B3--17 The thickness of the solum ranges from 20 to 28 inches. The depth to consolidated rock ranges from 20 to 36 inches. The texture of the A horizon is dominantly clay loam but ranges to clay. The color of the A horizon ranges from very dark grayish brown (10YR 3/2) and dark brown (7.5YR 3/2) to dark gray- ish brown (10YR 4/2). The texture of the B2 horizon ranges from heavy clay loam to silty clay and clay. The color ranges from dark brown (10YR 3/3, 7.5YR 3/3) to yellowish brown (10YR 5/4) and from dark reddish brown (5YR 3/4) to reddish brown (5YR 4/3). The structure of the B horizon ranges from weak to moderate subangular blocky. Jacana soils are associated with Descalabrado, Coamo, Glynn, Cornhill, and Fraternidad soils. They are deeper than Descalabrado soils, which are 20 inches or less deep over hard rock. They are shal- lower than Coamo and Glynn soils, both of which have a well-developed subsoil and occupy lower topograph- ic positions on alluvial fans and terraces, They are shallower and are less plastic in the underlying material than Cornhill soils. They are shallower, better drained, and less clayey than Fraternidad soils. Jacana clay loam, 2 to 5 percent slopes (JaB).-- This soil occurs on foot slopes in the western part of St. Croix. Included in mapping were small areas of Coamo clay loam on the nearly level parts of the landscape and small areas of San Anton clay loam that occur as narrow bands along drains. This Jacana soil has the profile described as representative for the series. The surface layer is 9 to 11 inches thick. The depth to the partly weathered volcanic rock is 20 to 28 inches. This soil is suited to pasture and woodland. Its use for cultivated crops is limited by adverse cli- matic conditions. It has only a slight limitation as a site for golf fairways. The slope and the 22 clayey texture are moderate limitations for camp- sites, picnic areas, intensive play areas, and buildings for light industry. Coarse fragments and shallowness over rock are severe limitations for use as a site for residences. (Capability unit IVe-3; woodland group 4; Hilly Clay range sites 2, 5, and 8, precipitation zones 45 to 60 inches, 35 to 45 inches, and 25 to 35 inches) Jacana clay loam, 5 to 12 percent slopes (JaC).-- This soil is on foot slopes and low rolling hills throughout volcanic areas, mainly on the island of St. Croix. Included in mapping were spots of Des- calabrado clay loam and small areas of a deeper soil that has a thin subsoil horizon (Bt) in which there is a significant accumulation of clay. The surface layer of this Jacana soil is 7 to ll inches thick. The depth to partly weathered volcan- ic rock is 18 to 28 inches. This soil is suited to pasture and woodland. use for cultivated crops is limited by the slope, the erosion hazard, the depth to hard rock, and adverse climate. It has a moderate limitation for campsites, picnic areas, golf fairways, trafficways, and buildings for light industry, and a severe limitation for residences and intensive play areas. (Capability unit IVe-3; woodland group 4; Hilly Clay range sites 2, 5, and 8, precipitation zones 45 to 60 inches, 35 to 45 inches, and 25 to 35 inches) Its Jacana clay loam, 12 to 20 percent slopes (JaD) .--This soil is on foot slopes and low rolling hills throughout the volcanic areas of St. Croix. Included in mapping were spots of Descalabrado clay loam. The surface layer of this Jacana soil is 6 to 9 inches thick. The depth to partly weathered volcan- ic rock is 16 to 26 inches. The depth to hard rock is 20 to 30 inches. This soil is suited to grassland and woodland. Its use for cultivated crops is limited by the slope, the erosion hazard, the depth to hard rock, and adverse climate. It has a moderate limitation for campsites, picnic areas, and trafficways, and a severe limitation for residences, buildings for light industry, intensive play areas, and golf fairways. (Capability unit VIe-1; woodland group 4; Hilly Clay range sites 2, 5, and 8, pre- cipitation zones 45 to 60 inches, 35 to 45 inches, and 25 to 35 inches) Jaucas Series The Jaucas series consists of excessively drained soils that formed in marine deposits of sand-sized particles of coral and seashells. These soils occur as hummocky areas along the coast, above high tide. The slope gradient is 0 to 5 percent. The climate is semiarid. The average annual rainfall is between 30 and 55 inches, and the average annual temperature is between 78° and 80° F. In a typical profile the surface layer is gray- ish-brown, calcareous sand about 6 inches thick. It contains many seashells. The underlying layers con- sist of light. brownish-gray and pale-brown calcare- ous sand and many fragments of coral.and seashells. The acreage is largely in seagrapes, coconuts, cocoplum (Icaco), and other drought-resistant plants. Scattered small areas are used for recreational pur- poses. Representative profile of Jaucas sand, 0 to 5 percent slopes, on Sandy Point, St. Croix, 200 feet north of the sea: A--0 to 6 inches, grayish-brown (10YR 5/2) sand; Single grain; loose; strongly calcareous; gradual, smooth boundary. 2 to 10 inches thick. Cl--6 to 16 inches, light brownish-gray (10YR 6/2) sand; single grain; loose; strongly calcare- ous; gradual, smooth boundary. 8 to 12 inches thick. to 26 inches, pale-brown (10YR 6/3) sand; single grain; loose; strongly calcareous; gradual, smooth boundary. 8 to 20 inches thick. C3--26 to 60 inches +, very pale brown (10YR 7/3) sand; single grain; loose; strongly calcare- ous. Many seashell and coral fragments the size of sand grains and a few large shell fragments mixed throughout profile. C2~-16 The texture is dominantly sand. The color of the A horizon ranges from dark grayish brown (10YR 4/2) to very pale brown (10YR 7/3) or white (10YR 8/2). Jaucas soils are associated with Diamond soils and with Tidal flats. They are deeper than Diamond soils, which are red clay loams and are only. about 14 inches deep over limestone. They are unlike Tidal flats in that this land type occurs right on the coast, is covered with sea water during high tide, and is strongly saline. Jaucas sand, 0 to 5 percent slopes (JuB).--This soil occurs as low, hummocky, sandy coastal areas on all three islands and on some small islands off- shore (pl. II). Included in mapping were small areas of coral, Tidal flats, and Limestone rock land. Low fertility, a low water-holding capacity, and very rapid permeability are severe limitations for most farm purposes, and the deep sand and high tide are severe limitations for most nonfarm purposes. (Capability unit VIIs-2; no woodland classification; Coastal Sand range site 11, all precipitation zones) Lavallee Series The Lavallee series consists of gently sloping, well-drained soils that are deep over volcanic rocks. These soils formed in gravelly clay loam sediments derived from these rocks. They occur on alluvial fans. The slope gradient is 2 to.5 per- cent. The climate is semiarid. The average annual rainfall is between 40 and 45 inches, and the aver- age annual temperature is between 78° and 80° F. In a typical profile the surface layer is dark- brown gravelly clay loam about 8 inches thick. The subsoil is dark-brown or reddish-brown, friable gravelly clay loam. At a depth of about 18 inches is dark-brown very gravelly loam that is about 50 percent volcanic rock fragments. Most of the acreage is cultivated and planted to subsistence crops. Representative profile of Lavallee gravelly clay loam, 2 to 5 percent slopes, on St. Croix, 300 feet west and 75 feet south of the road intersection to Cane Bay in the town of La Vallee: Ap--0 to 8 inches, dark-brown (10YR 3/3) gravelly clay loam; moderate, medium, granular struc- ture; very hard, friable, slightly sticky, nonplastic; common, fine, angular and sub- rounded fragments of volcanic rock; neutral; clear, smooth boundary. 6 to 12 inches thick. B21t--8 to 12 inches, dark-brown (7.5YR 3/2) gravel- ly clay loam; moderate, fine and medium, sub- angular blocky structure; hard, friable, slightly sticky, slightly plastic; few, thin, patchy clay films; common, fine and medium, subrounded fragments of volcanic rock; neu- tral; clear, smooth boundary. 4 to 6 inches thick. B22t--12 to 18 inches, reddish-brown (5YR 4/4) grav- elly clay loam; weak, medium, subangular blocky structure that breaks to moderate, fine, subangular blocky; hard, friable, slightly sticky, slightly plastic; few, thin, patchy clay films; many, fine and medium, subrounded and angular fragments of volcanic rock; many fragments the size of sand grains; few worm channels filled with soil material from B21t horizon; calcareous; mildly alka- line; gradual, smooth boundary. 8 to 12 inches thick. IIC--18 to 48 inches +, dark-brown (7.5YR 4/4) very gravelly loam; 50 percent volcanic rock frag- ments. The thickness of the solum ranges from 18 to 30 inches. Common to many fragments are scattered throughout. the profile. The color of the A horizon ranges from 10YR to 7.5YR in hue and 2 to 3 in chroma and value. The texture is dominantly gravelly clay loam but ranges to clay loam and loam, The texture of the B2t horizon is dominantly gravelly clay loam but ranges to gravelly loam, clay loam, and gravelly clay.. The structure of the B2t horizon ranges from weak to moderate subangular blocky. Patchy clay films are few to common. Below the B2t horizon are stratified lenses of gravelly loam, gravelly clay loam, loam, and gravel and thin lenses or pockets of secondary lime. In places there is a B3 horizon that has coated sand grains and a few patchy clay films. The color of the B3 horizon ranges from 7.5YR to 5YR in hue, and from 4 to 6 in value and chroma. The texture ranges from gravelly clay loam to gravelly loam. Lavallee soils are associated with San Anton, Glynn, and Parasol soils. They have a more strongly developed subsoil and.are more gravelly than San An- ton soils. They are less clayey and more gravelly 23 than Glynn soils. They are less yellow, are more gravelly, and have a lighter colored surface layer than Parasol soils. Lavallee gravelly clay loam, 2 to 5 percent slopes (LaB).--This soil is on terraces and alluvial fans near La Vallee and Christiansted on the island of St. Croix. Included in mapping were small areas of San Anton soils along drains, spots of Isaac gravelly clay loam, and steeper areas of Lavallee gravelly clay loam. This soil has only a slight erosion hazard and a slight limitation for most farm uses. The slope and the gravelly surface layer are moderate limitations for residences, buildings for light industry, traf- ficways, campsites, and picnic areas, and severe limitations for intensive play areas and golf fair- ways. (Capability unit IIe-2; woodland group 3; Deep range sites 1 and 4, precipitation zones 45 to 60 inches and 35 to 45 inches) Leveled Clayey Land Leveled clayey land (Lc) occurs east and south of the Alexander Hamilton Airport on St. Croix. The soil material in these areas was originally Aguirre clay, 0 to 2. percent slopes. Cutting, fill- ing, and leveling have removed much of the upper part of this soil and replaced it with a layer of marl. The material now is a mixture of marl and Aguirre clay. The shrinking and swelling of the clay, the plas- ticity and stickiness, and the slow percolation rate are severe limitations for all farm and nonfarm uses. (Capability unit VIIIs-1; no woodland or range classification) Leveled Marly Land Leveled marly land (Lm) is near the aluminum plant and the Alexander Hamilton Airport on St. Croix. It consists of leveled and reworked Aguilita and Sion soils. Originally both soils had a thin surface layer. Consequently, the reworked surface layer is largely marl or soft limestone. This land type has no value’ for farming. It has a moderate limitation for trafficways, because of moderate traffic-supporting capacity, and a severe limitation for residences and for buildings for light industry, because of low bearing strength. Stoniness and coarse fragments are moderate to severe limitations for all recreational uses. (Ca- pability unit VIIIs-1; no woodland or range classi- fication) Leveled Rocky Land Leveled rocky land (Lr) consists of areas where soils that are shallow and very shallow over volcan- ic rock have been blasted off or bulldozed. These areas occur at the western end of the Truman Airport on St. Thomas, where the ridge that extended from the Caribbean Hotel to the Virgin Islands College was 24 blasted and leveled and the surrounding areas were filled with rocky debris. Included in mapping were spots where the swamps or the tidal flats are filled with stones, cobblestones, and other rocky material. This land type has no value for farming. The hard rock at the surface is a severe to very severe limitation for all nonfarm purposes. (Capability unit VIIIs-1; no woodland or range classification) Limestone Rock Land Limestone rock land (Ls) consists of nearly level to steep areas where 70 to 90 percent of the surface is covered with outcrops of hard limestone or where erosion has removed the surface layer of soil mate- rial and exposed the underlying soft limestone, marl, or thin-bedded limestone. The slope gradient is 0 to 40 percent. Included in mapping were areas along the seacoast where coral outcrops are covered with as much as 6 inches of clayey sediments. The lack of soil material precludes all farm uses. The rockiness and the coarse fragments are severe to very severe limitations for all nonfarm uses. (Capability unit VIIIs-1; no woodland or range classification) Made Land Made land (Ma) consists of areas along the coast where sand has been dredged from the sea and used to fill the tidal flats and the tidal mangrove swamps to an elevation above sea level and above high tide. One large area is east of Christiansted, on St. Croix, near the radio tower. Another is west of Frenchtown in Charlotte Amalie, on St. Thomas. This land type is high in percentage of shell fragments and low in organic-matter content. This land type has severe limitations for all farm and nonfarm uses. (Capability unit VIIIs-1; no woodland or range classification) Magens Series The Magens series consists of moderately steep to steep, acid, well-drained soils that are deep over very highly decomposed basic volcanic rocks’ mixed with stones and boulders. These soils formed in ma- terial derived in place from these rocks. They oc- cur on side slopes of dissected volcanic uplands in the north-central part of St. Thomas. The slope gradient is 30 to 50 percent. The climate is semi- arid. The average annual precipitation is between 40 and 55 inches, and the average annual temperature is between 78° and 80° F. In a typical profile the surface layer is red- dish-brown and yellowish-red silty clay loam about 10 inches thick. The subsoil is red, friable grav- elly clay and clay. At a depth of about 49 inches is very highly decomposed volcanic rock that is var- legated red, brown, gray, and white. This material shows the original rock structure but can be crushed between the fingers. Most areas are in brush or brushy forest. Some are subdivided for housing developments. are used for crops or pasture. Representative profile of Magens silty clay loam, 30 to 50 percent slopes, on St. Thomas, 200 feet east on Jasmine road from the main entrance to the North Star Village housing development and 990 feet north of Mountain Top: Only a few All--0 to 7 inches, reddish-brown (5YR 4/4) silty clay loam; moderate, medium, granular struc- ture; friable, slightly sticky, slightly plastic; many fine roots; medium acid; clear, smooth boundary. 6 to 8 inches thick. Al2--7 to 10 inches, yellowish-red (5YR 4/6) silty clay loam; weak, medium, subangular blocky structure that breaks to moderate, medium, granular; friable, slightly sticky, plastic; common fine roots; strongly acid; clear, smooth boundary. 3 to 5 inches thick. B1--10 to 17 inches, red (2.5YR 4/6) gravelly clay; weak, medium, subangular blocky structure that breaks to moderate, fine, subangular blocky; friable, slightly sticky, slightly plastic; few fine roots; strongly acid; clear, smooth boundary. 5 to 9 inches thick. B21--17 to 26 inches, red (10R 4/6) clay; weak, coarse, subangular blocky structure that breaks to weak, medium, subangular blocky; friable, slightly sticky, slightly plastic; thin discontinuous clay films; few roots; strongly acid; gradual, smooth boundary. 8 to 10 inches thick. B22--26 to 42 inches, red (10R 4/6) clay; weak, coarse, subangular blocky structure that breaks to weak, fine and medium, subangular blocky; friable, slightly sticky, slightly plastic; thin discontinuous clay films; few roots; strongly acid; gradual, smooth bound- ary. 10 to 18 inches thick. B3--42 to 49 inches, red (10R 4/6) silty clay loam; weak, medium and coarse, subangular blocky structure; friable, slightly sticky, slight- ly plastic; thin discontinuous coatings; few fine pores; approximately 30 percent sapro- lite; strongly acid; gradual, wavy boundary. 5 to 9 inches thick. C--49 to 84 inches, saprolite; variegated red, yel- lowish brown, gray, and white and appears to have a rubbed color of red (10R 4/6); mas- sive; few clay coatings on fracture planes. The thickness of the solum ranges from 35 to 60 inches. The reaction ranges from strongly acid to medium acid (pH 5.1 to 6.0). The texture is domi- nantly silty clay loam but ranges to clay loam and silty clay. The color of the A horizon ranges from dark reddish gray (5YR 4/2) to yellowish red (5YR 4/6). The color of the B2 horizon is red (2.5YR 4/6 or 10R 4/8). The texture of this horizon is domi- nantly clay. The structure ranges from weak, coarse, subangular blocky to weak, fine, subangular blocky. The B3 horizon is 25 to 50 percent sapro- lite. A few subrounded stones, 12 to 24 inches in diameter, of more resistant volcanic material are scattered throughout the profile. At a depth of about 16 inches is a weak stone line that consists of small angular volcanic fragments and a few cob- blestones 3 to 6 inches in diameter. Magens soils are associated with Cramer, Isaac, Dorothea, and Victory soils. All are on steep vol- canic uplands. Magens soils are deeper than Cramer soils, which are less than 20 inches over hard vol- canic rock. They are deeper and have a lighter colored surface layer than Isaac soils. They differ from Dorothea soils in being red instead of yellow and in having a more weakly developed subsoil. They differ from Victory soils in being red instead of yellow and in having a more strongly developed sub- soil. Magens silty clay loam, 30 to 50 percent slopes (MgF).--This soil is on side slopes of dissected volcanic uplands in north-central St. Thomas. In- cluded in mapping were spots of Cramer, Dorothea, and Victory soils; spots where the subsoil is yel- lowish red; and spots where there are angular rock fragments on the surface. This soil is suited to pasture and woodland. It is deep and easy to work, but the slope and the ero- sion hazard preclude its use for cultivated crops. The slope and the hazard of slides severely limit all nonfarm uses. (Capability unit VIe-2; woodland group 1; Hilly Clay range sites 2 and 5, precipita- tion zones 45 to 60 inches and 35 to 45 inches) Parasol Series The Parasol series consists of gently sloping to moderately sloping, well-drained soils that are deep over granitic rock (gabbro). These soils formed in clay loam and clayey sediments derived from this ma- terial. They occur on foot slopes and alluvial fans, mainly in the Fountain area on St. Croix. The slope gradient is 2 to 12 percent. The climate is semiarid. The average annual rainfall is between 45 and 50 inches, and the average annual temperature is between 78° and 80° F. In a typical profile the surface layer is very dark brown clay loam about 13 inches thick. The up- per part of the subsoil is brown, firm clay. The lower part is dark yellowish-brown, friable clay loam. At a depth of about 40 inches is brown, fria- ble loam, sandy loam, and loamy sand, all derived from granitic rock. Most of the acreage is used for sugarcane. The rest is in guineagrass and native grasses. Representative profile of Parasol clay loam, 5 to 12 percent slopes, on St. Croix, 1.3 miles north of an oil road on the road to River and 100 feet south and 75 feet west of Gate: Ap--0 to 7 inches, very dark brown (10YR 2/2) clay loam; moderate, medium, granular structure; friable, slightly sticky, slightly plastic; many sand grains; few roots; neutral; clear, smooth boundary. 4 to 8 inches thick. Al--7 to 13 inches, very dark brown (10YR 2/2) clay 25 loam; weak, medium, subangular blocky struc- ture that breaks to moderate, medium, granu- lar; friable, slightly sticky, slightly plas- tic; many sand grains; few roots; neutral; clear, smooth boundary. 4 to 8 inches thick. B2t--13 to 24 inches, brown (10YR 4/3) clay; moder- ate, medium, subangular blocky structure; hard, firm, slightly sticky, slightly plas- tic; thin, discontinuous, dark-brown (10YR 3/3) clay films on peds and in root channels; many dark-brown worm casts 1 to 2 millimeters in diameter; few roots; numerous sand grains; neutral; gradual, smooth boundary. 8 to 12 inches thick. B3--24 to 40 inches, dark yellowish-brown (10YR 4/4) clay loam; weak, coarse, subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; thin, discontinu- ous, very dark grayish-brown (10YR 3/2) coat- ings on vertical ped surfaces and in root channels; very few roots; numerous sand grains; numerous old root channels that have very dark brown organic coatings; neutral; gradual, smooth boundary. 8 to 18 inches thick. Cl--40 to 52 inches, brown (10YR 4/3) loam (sapro- lite); massive; friable, nonsticky, nonplas- tic; few, thin, patchy clay films along frac- ture planes; few calcareous feldspar crys- tals; neutral; gradual, smooth boundary. 8 to 20 inches thick. C2--52 to 62 inches, brown (10YR 4/3) sandy 1toam (saprolite); massive; very friable, non- sticky, nonplastic; few calcareous feldspar crystals, partly weathered; neutral; gradual, smooth boundary. C3--62 to 80 inches, brown (10YR 5/3) coarse loamy sand (saprolite); massive. The thickness of the solum ranges from 24 to 46 inches. The color of the A horizon ranges from very dark grayish brown (10YR 3/2) to very dark brown (1OYR 2/2). The texture is dominantly clay loam, The color of the B2t horizon ranges from brown (10YR 4/3) to dark yellowish brown (10YR 3/4). The tex- ture is dominantly clay but ranges to silty clay. The structure is moderate, medium, subangular blocky. There are a few thin, patchy to discontin- uous clay films, The color of the B3 horizon ranges from dark yellowish brown (10YR 4/4) to brown (10YR 4/3), and the texture from clay loam to loam. The structure is dominantly weak, coarse, subangular blocky. Clay films range from few thin patchy to thin discontinuous on the vertical cleavage planes and in’root channels. Parasol soils are associated with Coamo, Laval- lee, Glynn, Southgate, and Jacana soils. They do not have the horizon of accumulated calcium carbon- ate that is typical of Coamo soils. They do not have the red colors that are typical of Lavallee soils and they are not gravelly. They have a more friable surface layer than Glynn soils and are neu- tral throughout instead of alkaline. They are deep- er over rock and occur in lower topographic posi- tions than Southgate soils. They are deeper than 26 Jacana soils, which are only 20 to 36 inches deep over hard volcanic rock. Parasol clay loam, 2 to 5 percent slopes (PaB).-- This soil is on St.-Croix, on foot slopes and allu- vial fans near Fountain and River. Included in map- ping were spots of Jacana clay loam, Southgate clay loam, and San Anton clay loam. The surface layer of this Parasol soil is very dark brown clay loam 10 to 16 inches thick: The upper part of the subsoil is clay 8 to 12 inches thick. Below this is highly decomposed rock. This soil is suited to cultivated crops, pasture, and woodland. It has no limitation or only a slight limitation for residences, buildings for light in- dustry, trafficways, and golf fairways, and a mod- erate limitation for campsites, picnic areas, and intensive play areas. (Capability unit Ile-2; woodland group 3; Hilly Clay range sites 2 and 5, precipitation zones 45 to 60 inches and 35 to 45 inches) Parasol clay loam, 5 to 12 percent slopes (PaC).--This soil is on St. Croix, on foot slopes and alluvial fans near Fountain and River and just south of Christiansted. Included in mapping, and making up 5 to 10 percent of each mapped area, were spots of Jacana clay loam, spots of Southgate clay loam, and spots of steeper Parasol clay loam. This Parasol soil has the profile described as representative for the series. This soil is suited to pasture and woodland. It is moderately limited for cultivation because of the slope and the erosion hazard. It has no limitation or only a slight limitation for residences and trafficways, a moderate limitation for campsites, picnic areas, golf fairways, and buildings for light industry, and a severe limitation, because of slope, as a.site for intensive play areas, (Ca- pability unit IIIe-1; woodland group 3; Hilly Clay range sites 2 and 5, precipitation zones 45 to 60 inches and 35 to 45 inches} Pozo Blanco Series The Pozo Blanco series consists of gently sloping to moderately sloping, well-drained, calcareous soils that are moderately deep over thin-bedded soft limestone. These soils formed in clay loam sedi- ments derived from limestone and basic volcanic rocks. They occur on foot slopes in the northern part of St. Thomas and in the western and central parts of St. John. The slope gradient is 5 to 20 percent. The climate is semiarid. The average an- nual rainfall is between 35 and 45 inches, and the average annual temperature is between 78° and 80° F. In a typical profile the surface layer is very dark grayish-brown clay loam about 6 inches thick. The upper part of the subsoil is dark grayish-brown, firm clay loam, The lower part is brown, friable, calcareous silty clay. loam, At a depth of about 18 inches is light-gray, very friable, calcareous loam thin-bedded with soft limestone. Almost all the acreage is in guineagrass and na- tive grasses and is used as pasture. Representative profile of Pozo Blanco clay loam, 5 to 12 percent slopes, in a guineagrass pasture on St. Thomas, 2,200 feet east of Lovenlund, 1,000 feet west of Mandal, and 200 feet north of the road: Ap--0 to 6 inches, very dark grayish-brown (10YR 3/2) clay loam; moderate, medium, granular structure; firm, slightly sticky, slightly plastic; many fine roots; few fine fragments; neutral; clear, smooth boundary. 4 to 8 inches thick. B2--6 to 13 inches, dark grayish-brown (10YR 4/2) clay loam; weak, fine, subangular blocky structure; firm, slightly sticky, slightly plastic; common fine roots; mildly alkaline; clear, smooth boundary. 6 to 8 inches thick. B3ca--13 to 18 inches, brown (10YR 5/3) silty clay loam; weak, fine and medium, subangular blocky structure; friable, slightly sticky, slightly plastic; few fine roots; calcareous; lime coatings on ped surfaces; abrupt, smooth boundary. 4 to 6 inches thick. C--18 to 48 inches, light-gray (10YR 7/2) loam; mas- sive; very friable, nonsticky, slightly plas- tic; calcareous. This horizon is thin-bed- ded, soft limestone. The thickness of the solum ranges from 14 to 20 inches. Limestone and volcanic fragments range from none to many. The texture of the A horizon ranges from gravelly clay loam or clay loam to loam. The color of the A horizon is 10YR in hue, 2 and 3 in value, and 1 to 4 in chroma. The color of the B2 horizon ranges-from dark gray (10YR 4/1) and dark grayish brown (10YR 4/2) to dark yellowish brown (10YR 4/4). The texture ranges from gravelly clay loam to clay loam. The structure of the B2 horizon ranges from weak, medium, prismatic to weak, fine and medium, subangular blocky. The color of the B3ca ranges from dark yellowish brown (10YR 4/4) to brown (10YR 5/3, 10YR 4/3), and the texture ranges from clay loam to silty clay loam. The structure of this horizon is dominantly weak subangular blocky. The material in the C horizon ranges from soft lime- stone to highly weathered calcareous volcanic rock. The color ranges from pale yellow (2.5Y 8/4) or yel- low (10YR 7/6) to white and light gray (5Y 7/1) and greenish gray (5BG 6/1). Pozo Blanco soils are associated with Aguilita, Fredensborg, and Sion soils. They differ from all of these soils in having a layer of accumulated cal- cium carbonate. They are deeper and less grav- elly than Aguilita soils. Pozo Blanco clay loam, 5 to 12 percent slopes (PbC).--This soil occurs on foot slopes in the northern part of St. Thomas and in the central and western parts of St. John. Included in mapping were spots of Aguilita gravelly clay loam and Isaac clay loam. This Pozo Blanco soil has the profile described as representative for the series. The surface layer is 4 to 8 inches thick. is 14 to 20 inches. This soil is suited to grassland and woodland but is not generally suited to cultivated crops. The slope is a severe limitation, and the erosion hazard is severe in cultivated areas that are not protected by a vegetative cover. The limitation is none to slight for dwellings and trafficways, moderate for campsites, picnic areas, golf fairways, paths and trails, and buildings for light industry, and severe for intensive play areas. (Capability unit IVe-1; woodland group 2; Hilly Clay range sites 5 and 8, precipitation zones 35 to 45 inches and 25 to 35 inches) The depth to soft limestone Pozo Blanco clay loam, 12 to 20 percent slopes (PbD) .--This soil occurs on foot slopes in the northern part of St. Thomas and in the central and western parts of St. John. Included in mapping were spots of Aguilita gravelly clay loam and Isaac clay loam. This Pozo Blanco soil has been affected by geo- logic erosion. The surface layer is 4 to 7 inches thick. The depth to soft limestone is 14 to 18 inches. This soil is suited to pasture and woodland but is not generally suited to cultivated crops. The slope is a severe limitation, and the erosion hazard is severe in cultivated areas that are not protected by a vegetative cover. The limitation is moderate for dwellings, trafficways, campsites, picnic areas, and paths and trails, and severe for golf fairways, intensive play areas, and buildings for light industry. (Capability unit VIe-3; wood- land group 2; Hilly Clay range sites 5 and 8, pre- cipitation zones 35 to 45 inches and 25 to 35 inches) San Anton Series The San Anton series consists of nearly level to moderately sloping, well-drained soils that are deep over limestone and volcanic rocks. These soils formed in stratified sediments derived from these rocks. They occur on flood plains and alluvial fans on the three main islands. The slope gradient is 0 to 12 percent. The climate is semiarid. The average annual rainfall is between 35 and 50 inches, and the average annual temperature is between 78° and 80° F. In a typical profile the surface layer is very dark grayish-brown clay loam about 9 inches thick. The subsoil is brown, friable gravelly clay loam. At a depth of about 21 inches is brown, friable, calcareous gravelly clay loam that grades to yellow- ish-brown, firm, calcareous clay loam. This materi- al contains some rock fragments. Most of the acreage is in grasses and is used as pasture. Part of it is used for cultivated crops. Representative profile of San Anton clay loam, 0 to 3 percent slopes, in a guineagrass pasture on St. Croix, five-tenths of a mile east of the coast road, which is north of Fredericksted, on the road to Orangegrove, and 50 feet south of the road: 27 Ap--0 to 9 inches, very dark grayish-brown (10YR 3/2) clay loam; moderate, medium, granular structure; friable when moist, slightly sticky and slightly plastic when wet; few, fine, black minerals; common; fine and medi- um, angular volcanic fragments; common fine roots: neutral; clear, smooth boundary. 6 to 12 inches thick. B--9 to 21 inches, brown (10YR 4/3) gravelly clay loam; weak, medium, subangular blocky struc- ture that breaks to weak, fine, subangular blocky; friable when moist, slightly sticky and slightly plastic when wet; common, fine and medium, angular volcanic fragments; few, fine, black minerals; few fine limestone fragments; common fine roots; neutral; clear, smooth boundary. 8 to 14 inches thick. Cl--21 to 32 inches, brown (10YR 4/3) gravelly clay loam; massive; friable when moist, slightly sticky and slightly plastic when wet; few fine roots; few, fine, black concretions; calcareous; abrupt, smooth boundary. 8 to 14 inches thick, TIC2--32 to 50 inches, yellowish-brown (10YR 5/4) clay loam; massive; firm when moist, slightly sticky and slightly plastic when wet; few fine roots; common, fine, black minerals; calcareous. Thickness of the solum ranges from 14 to 26 inch- es. The texture of the A horizon ranges from clay loam and silty clay loam to silty clay. The color is 1O0YR to 5YR in hue, 2 to 4 in value, and 2 to 3 in chroma. The texture of the B horizon ranges from gravelly clay loam to silty clay loam and loam. The color is 10YR to 5YR in hue, 2 to 4 in value, and 2 to 4 in chroma. The structure ranges from weak, fine, subangular blocky to weak, medium, subangular blocky. The C horizon is stratified. The texture ranges from silty clay loam to loamy sand, and there are varying amounts of gravel. The color of the C horizon is 10YR to 5YR in hue, 4 to 5 in value, and 2 to 4 in chroma. Below a depth of 40 inches, the color ranges from yellowish brown (10YR 5/4) to olive (5Y 4/4) and olive brown (2.5Y 4/4). The re- action ranges from slightly acid to alkaline. San Anton soils are associated with Glynn, Coamo, Lavallee, and Cornhill soils. They have a thin- ner, less clayey, more weakly developed subsoil than Glynn soils. They are less red, have a thinner sub- soil, and are less gravelly than Lavallee soils. They are less clayey in the subsoil than Coamo soils, which have calcareous, stratified underlying layers. They are less plastic and clayey in the underlying material than Cornhill soils. San Anton clay loam, 0 to 3 percent slopes (SaA).--This soil is on alluvial fans and narrow flood plains along drains on all three of the main islands. Included in mapping, and making up less than 10 percent of each mapped area, were spots of Coamo clay loam and Glynn clay loam, and in some areas, spots of gravelly soils that formed in recent alluvium. 28 This San Anton soil has the profile described as representative for the series. This soil is suited to cultivated crops, pasture, and woodland. Lack of effective rainfall limits the choice of crops. In areas not subject to flooding, the limitation is none to slight for all nonfarm uses. (Capability unit IIc-1; woodland group 3; Deep range sites 1, 4, and 7, precipitation zones 45 to 60 inches, 35 to 45 inches, and 25 to 35 inches) San Anton clay loam, 5 to 12 percent slopes (SaC).--This soil is on alluvial fans and dissected, narrow flood plains along drains on all three of the main islands. Included in mapping were spots of Descalabrado clay loam and Cramer gravelly clay loam. The ‘surface layer of this San Anton soil is 6 to 9 inches thick, and the solum is 14 to 22 inches thick. This soil is suited to cultivated crops, pasture, and woodland. The slope limits the choice of crops, and the erosion hazard is severe in cultivated areas that are not protected by a vegetative cover. The limitation is none to slight for dwellings and trafficways, moderate for buildings for light in- dustry, golf fairways, campsites, picnic areas, and paths and trails, and severe for intensive play areas. (Capability unit IIIe-1; woodland group 3; Deep range sites 1, 4, and 7, precipitation zones 45 to 60 inches, 35 to 45 inches, and 25 to 35 inches) Sion Series The Sion series consists of nearly level to mod- erately sloping, well-drained soils that are shallow over soft limestone or marl. These soils formed in calcareous clay loam sediments derived from this ma- terial, They occur near coastal areas, in valleys and on foot slopes in the southern part of St. Croix. The slope gradient is 0 to 12 percent. The climate is semiarid. The average annual rainfall is between 30 and 35 inches, and the average annual temperature is between 78° and 80° F. In a typical profile the surface layer is very dark grayish-brown clay loam about 12 inches thick. The subsoil is grayish-brown, friable, calcareous clay loam. At a depth of about 17 inches is very pale brown and white, soft limestone or marl. Most of the acreage is cultivated to row crops. Uncultivated areas are in guineagrass and are used as pasture. Representative profile of Sion clay loam, 0 to 5 percent slopes, in a cultivated field on St. Croix, half a mile west and 50 feet south of the entrance to the Experiment Station near Annas Hope: Ap--0 to 12 inches, very dark grayish-brown (10YR 3/2) clay loam, brown (10YR 5/3) when dry; weak, fine, granular structure; slightly hard, friable, slightly sticky, slightly plastic; many, fine and medium, limestone fragments; calcareous; moderately alkaline; 4 ‘weoyt AeyTS eayjosog uo sadei1a} yoo y *sadojs Juasied QP 03 OZ ‘weo] AeTS Opeiqeleosag e AT[oA IaWeID Jo aTtjoig *weol Ajo Ayjaaei3 eltjindy jo aTtjoig oe te }s [eTJUS}Jod saonpa1 adoj[g *sadoys juasdied *sado[s }uadiad ¢ 0} Z *Ae{D Bioqsuapaiy st [Ios ay TD BaYyjJOIOG UT VOT}ONI}JsUOD JapuN pucd wie -ysniq Aagay ur pa}ue[diapun AueSoyew sésmpuoy ~ *sadojs Juaoied OF 03 OZ ‘uBoT Aeto Aj] @eABis eyT[INSy st punoidy9eq UI Bole papoom daalsg ‘puss seone[f *sodojs yuoosad ¢ 0} Z ‘ABl> Bioqsuepaesy uo auesiedng Tl VWtd clear, smooth boundary. 8 to 12 inches thick. B--12 to 17 inches, grayish-brown (10YR 5/2) clay loam, light brownish gray (10YR 6/2) when dry; weak, fine, granular structure; slightly hard, friable, slightly sticky, slightly plastic; calcareous; many, fine and medium limestone fragments; moderately alkaline; abrupt, smooth boundary. 2 to 8 inches thick. C--17 to 50 inches, soft, very pale brown (10YR 7/3) limestone or marl. This material is easily penetrated with a spade or an auger, The thickness of the solum ranges from 10 to 20 inches. Few to common limestone fragments are mixed throughout the profile. The color of the A horizon is dominantly 10YR in hue, 2 or 3 in value, and 2 to 5 in chroma. The texture ranges from clay loam to silty clay loam, and the structure ranges from weak, fine, granular to moderate, medium, granular. The- color of the B horizon ranges from brown (10YR 5/3) to grayish brown (10YR 5/2), and the texture ranges from silty clay loam and clay loam to silt loam. Sion soils are associated with Aguilita, Fredens- borg, Hesselberg, and Diamond soils. They are deep- er and are less gravelly than Aguilita soils. They are less clayey in the surface, layer than Fredens- borg soils. They are not so red as Hesselberg and Diamond soils, both of which overlie limestone. Sion clay loam, 0 to 5 percent slopes (ScB).-- This soil occurs in valleys and on foot’ slopes in the southern and southwestern parts of St. Croix. Included in mapping were spots of Fredensborg clay, Hesselberg clay, and Diamond clay loam. This Sion soil has the profile described as rep- resentative for the series. The surface layer is 10 to 12 inches thick. The texture is clay loam to a depth of 16 to 20 inches. This soil can be used for cultivated crops, pas- ture, and woodland. Shallowness over rock and in- sufficient effective rainfall limit the choice of crops. The limitation is none to slight for dwell- ings and golf fairways, and moderate for traffic- ways, buildings for light industry, campsites, and picnic areas. (Capability unit IIIsc-1; woodland group 2; Shallow range site 6, precipitation zone 35 to 4S inches) Sion clay loam, 5 to 12 percent slopes (ScC).-- This soil is on foot slopes in the southern and southwestern parts of St. Croix. Included in map- ping were spots of Aguilita gravelly clay loam and Fredensborg clay and spots where the slope is more than 12 percent. The surface layer of this Sion soil is 8 to 10 inches thick. The texture is clay loam to a depth of 10 to 16 inches. This soil is suited to pasture and woodland. It can be used occasionally for cultivated crops, but the erosion hazard is very severe in cultivated areas that are not protected by a cover of vegeta- tion. The limitation is slight for residences, moderate for campsites, picnic areas, golf fairways, 382-314 O- 70-3 trafficways, and buildings for light industry, and severe: for intensive play areas. (Capability unit IVe-1; woodland group 2; Shallow range site 6, pre- cipitation zone 35 to 45 inches) Southgate Series The Southgate series consists of strongly slop-' ing to steep, well-drained soils that are shallow over granitic rocks. These soils formed in gravelly clay loam material derived in place from these rocks. They occur on mountain slopes, mainly in the north-central part of St. Croix. The climate is semiarid. The average annual rainfall is between 30 and 50 inches, and the average annual temperature is between 78° and 80° F. , In a typical profile the surface layer is very dark grayish-brown clay loam about 7 inches thick. It contains angular rock fragments. The subsoil is dark-brown, friable gravelly loam and is 50 percent gravel-sized rock fragments. At a depth of about 12 inches is partly decomposed granitic rock. Below this, at a depth of about 18 inches, is harder granitic rock. Most of the acreage is in native grasses, guinea- grass, and brush and is used as pasture. Representative profile of Southgate clay loam, 12 to 40 percent slopes, at an elevation of approxi- mately 300 feet on the south slope of Maria Hill, on St. Croix, four-tenths of a mile east of Lowrys Hill ruins: Ap--0 to 7 inches, very dark grayish-brown (10YR 3/2) clay loam; moderate, medium, granular structure; friable, slightly sticky, slightly plastic; common fine roots; few sand grains; common angular rock fragments; medium acid; clear, smooth boundary. 5 to 10 inches thick. B--7 to 12 inches, dark-brown’ (10YR 3/3 rubbed color) gravelly loam; weak, fine, subangular blocky structure; friable, nonsticky, non- plastic; 50 to 60 percent volcanic rock frag- ments the size of pebbles; few fine roots; medium acid; clear, smooth boundary. 4 to 8 “inches thick. C--12 to 18 inches, partly weathered, intrusive vol- canic rock; reddish-brown (2.5YR 4/4) stain- ing on fracture planes; few fine roots along fracture planes; slightly acid; gradual, wavy boundary. 4 to 10 inches thick. R--18 inches, semiconsolidated, intrusive volcanic rock. The depth to semiconsolidated volcanic rock ranges from 9 to 20 inches. Common to many volcanic fragments are mixed throughout the profile. The reaction ranges from medium acid to slightly acid. The color of the A horizon ranges from very dark grayish brown (10YR 3/2) and very dark brown (10YR 2/2) to dark yellowish brown (10YR 3/4}. The tex- ture ranges from clay loam to gravelly clay loam. The color of the B horizon is 7.5YR and 10YR in hue, 3 to 5 in value, and 3 to 4 in chroma. The texture ranges from gravelly loam to gravelly clay loam. 29 The structure of the B horizon ranges from weak, fine, subangular blocky to weak, medium, subangular blocky. Southgate soils are associated with Descalabrado, ‘Cramer, and Parasol soils and Volcanic rock land. They. are more gravelly in the subsoil than Descala- brado soils. In comparison with Cramer soils, their subsoil is thinner and is dark-brown gravelly loam instead of dark-red and dark reddish-brown gravelly clay. They are shallower over granitic rock than Parasol soils, which occur on foot slopes below Southgate soils. Southgate clay loam, 12 to 40 percent slopes (SgE).--This soil is on side slopes and ridgetops on St. Croix, mainly near Fountain and River. It also occurs as a small area southeast of Christian- sted. Included in mapping were spots of Descala- brado clay loam and Parasol clay loam. This Southgate soil has the profile described as representative for the series. The surface layer is 7 to 10 inches thick. The depth to rock ranges from 12 to 20 inches. ; This soil is suited to pasture and woodland. Most of the acreage is used for pasture. Shallow- ness over rock, the slope, and the erosion hazard preclude cultivation. The limitation is severe for all nonfarm uses. (Capability unit VIs-3; woodland group 4; Shallow range sites 6 and 9, precipitation zones 35 to 45 inches and 25 to 35 inches) Southgate clay loam, 40 to 60 percent slopes (SgF).--This soil occurs on side slopes of dissected granitic uplands in the Fountain area on St. Croix and on some of the offshore islands. Included in mapping were spots of Descalabrado clay loam, and, making up 10 to 15 percent of.each mapped area, spots of Volcanic rock land where the soil is less than 6 inches thick over rock. The surface layer of this Southgate soil is 5 to 8 inches thick. The depth to rock ranges from 9 to 18 inches. This soil is suited to pasture and woodland. The very steep slopes, the shallowness over rock, and the coarse fragments preclude cultivation. The limi- tation is severe for all nonfarm uses. (Capability unit VIIs-3; woodland group 4; Shallow range sites 6 and 9, precipitation zones 35 to 45 inches and 25 to 35 inches) Southgate-Rock land compiex, 20 to 60 percent slopes (SrF).--This complex consists of Southgate soils and areas that are 50 to 70 percent rock out- crops and have soil material less than 5 inches thick. Loose stones and boulders are common on the surface. This complex occurs on all three Virgin Islands and on some of the offshore islands. Southgate soils occur between the rock outcrops. They are dark grayish-brown, dark-brown, and yellow- ish-brown clay loams 6 to 20. inches thick. The rocks are fresh exposures of lava, breccia, and tuff. This complex has no value. for farming. Most of the acreage is brushy forest or brushy pasture. The shallowness over rock, the steep slopes, and the 30 coarse fragments preclude cultivation and make it difficult to establish and maintain pasture and woodland. The limitation is severe for all nonfarm uses. (Capability unit VIIs-3; no woodland classi- fication; Rough Stony Land range site 10, all pre- cipitation zones) Tidal Flats Tidal flats (Tf) occurs as nearly level, essen- tially barren areas that are periodically covered- with tidal water. Some of the lower parts are covered daily. The higher parts are covered during high tide and during periods when they receive ex- cessive runoff from the surrounding mountains. The soil material is silty and clayey and in places con- tains a considerable amount of very fine sand. Gen- erally it is high in soluble salts. This material cracks when dry. This land type can be used only for wildlife hab- itat or esthetic purposes, Extreme wetness pre- cludes its use for commercial production of crops, forage, and trees. The limitation is severe to very severe for most engineering and recreational uses. (Capability unit VIIIw-1; no woodland classifica- tion; no range classification) Tidal Swamp Tidal swamp (Ts) occurs along inlets and along the seacoast. It is usually covered with salt wa- ter. The vegetation is a thick growth of mangrove trees. The soil material is light colored, saline, and sandy or clayey. It contains a considerable amount. of mucky and peaty organic material derived from the decaying mangrove trees. The underlying material consists of coral, shells, limestone, marl, or clay. This land type can be used as habitat for birds and as feeding and breeding areas for oysters and crabs. It has no agricultural value. Flooding pre- cludes its use for most engineering and recreational uses. Some of the mangrove wood is used in making charcoal. (Capability unit VIIIw-1; no woodland classification; no range classification) Victory Series The Victory series consists of strongly sloping to steep, well-drained soils that are deep over highly decomposed, basic volcanic rocks mixed with a few less highly decomposed boulders. These soils formed. in clay loam material derived in place from these rocks. They are on side slopes and ridgetops of maturely dissected volcanic uplands. Most of the acreage is on St. Thomas. It occurs as a ridge that includes Crown Mountain, Signal Hill, and some of the other higher peaks. The slope gradient is 12 to 40 percent. The climate is semiarid. The average annual rainfall is between.40 and 55 inches, and the average annual temperature is between 78° and 80° F. In a typical profile the surface layer is dark yellowish-brown clay loam, is about 9 inches thick, and contains a few volcanic rock fragments. The subsoil is strong-brown clay loam. The upper part is firm; the lower part is friable. At a depth of about 30 inches is strong-brown, friable, highly de- composed volcanic rock. Most areas are used for pasture and cultivated crops. Some are subdivided for housing develop- ments. Representative profile of Victory clay loam, 12 to 20 percent slopes, on St. Thomas, 200 feet west of the Lilliendahl road junction and 1,400 yards east of the Dorothea Experiment Station: Al--0 to 9 inches, dark yellowish-brown (10YR 3/4) clay loam; moderate, medium, granular struc- ture; slightly hard, friable, slightly sticky, slightly plastic; few, fine, volcanic rock fragments; slightly acid; clear, smooth boundary. 7 to 11 inches thick. B2--9 to 17 inches, strong-brown (7.5YR 5/6) clay loam; weak, medium, subangular blocky struc- ture; very hard, firm, slightly sticky, slightly plastic; very few, thin, patchy clay films; few, fine, volcanic rock fragments; slightly acid; gradual, smooth boundary. 6 to 10 inches thick. B3--17 to 22 inches, strong-brown (7.5YR 5/6) clay loam; weak, medium, angular blocky structure; hard, friable, slightly sticky, slightly plastic; common fine volcanic fragments; 40 percent saprolite; slightly acid; gradual, wavy boundary. 4 to 7 inches thick. C--22 to 60 inches +, strong-brown (7.5YR 5/6) saprolite; massive; hard, friable, slightly sticky, nonplastic; slightly acid. The thickness of the solum ranges from 17 to 28 inches. The texture is dominantly clay loam but ranges to silty clay loam. The reaction ranges from medium acid to neutral (pH 5.6 to 7.3). The color of the A horizon ranges from dark brown (7.5YR 3/2 or 10YR 3/3) to brown (7.5YR 4/2 or 10YR 4/3) and dark yellowish brown .(10YR 3/4 or 4/4). The texture of the B horizon ranges from clay loam to gravelly clay loam. The color of the B horizon ranges from yellowish brown (10YR 5/4, 5/6, or 5/8) to strong brown (7.5YR 5/6 or S/8).. The structure ranges from weak, medium, subangular blocky to weak, coarse, subangular blocky. Angular volcanic fragments range from few. to common in the B horizon. The B3 horizon is 30 to 50 percent saprolite. Victory soils are associated with Descalabrado, Dorothea, Cramer, Isaac, and Magens soils. They are deeper, browner, and more acid than Descalabrado soils, and they are underlain by more highly decom- posed material. They have a more weakly developed subsoil than Dorothea soils. In comparison with Cramer soils, they are deeper, have a more weakly developed subsoil, have softer underlying material, and are yellowish brown instead of reddish brown. They are less clayey and have a more weakly devel- oped subsoil than Isaac soils and are yellowish brown instead of reddish brown. They are shallower than Magens soils and are yellowish brown instead of reddish brown. Victory clay loam, 12 to 20 percent slopes (VcD).--This soil is on side slopes and ridgetops, mainly in the central part of St. Thomas. It also occurs as a small acreage in the northwestern part of St. Croix. Included in mapping were spots of Dorothea clay loam, Descalabrado clay loam, and Cramer gravelly clay loam. This Victory soil has the profile described as representative for the series. The surface layer is 8 to 11 inches thick. The subsoil extends to a depth of 20 to 28 inches. This soil is limited to use as pasture, woodland, and wildlife habitat. The strong slope makes it un- suitable for cultivation, and the erosion hazard is severe in cultivated areas that do not have a pro- tective cover of vegetation. The limitation is mod- erate for dwellings, trafficways, campsites, picnic areas, paths, and trails, and severe for buildings for light industry or other commercial purposes, intensive play areas, and golf fairways. (Capabil- ity unit VIe-1; woodland group 1; Hilly Clay range site 2, precipitation zone 45 to 60 inches) Victory clay loam, 20 to 40 percent slopes (VcE).--This soil is on side slopes, mainly in the northern part of St. Thomas. It also occurs as a smal] acreage in the northwestern part of St. Croix. Included in mapping were spots of Dorothea clay loam, Descalabrado clay loam, and Cramer gravelly clay loam, The surface layer of this Victory soil is 7 to 10 inches thick. The subsoil extends to a depth of 17 to 25 inches. This soil is limited to use as pasture, woodland, and wildlife habitat. The steep slope makes it un- suitable for cultivation, and the erosion hazard is severe in cultivated areas that do not have a pro- tective cover of vegetation. The limitation is severe for most engineering and recreational uses. (Capability unit VIe-1; woodland group 1; Hilly Clay range site 2, precipitation zone 45 to 60 inches) Volcanic Rock Land Volcanic rock land (Vr) is made up of areas where volcanic rock outcrops cover 50 to 70 percent of the surface. Between the outcrops is very shallow, dark yellowish-brown, gravelly loam soil material. Loose stones and boulders are common. The slope gradient is 60 to 70 percent. The vegetation is brushy for- est or brushy pasture. This land type occurs on the three larger islands and on some offshore smaller islands. This land type is restricted to wildlife habitat and esthetic purposes. The very steep slopes, ex- posed rock, and shallow soil material preclude its use for commercial production of crops; forage, or trees and severely limit all engineering and recrea- tional uses. (Capability unit VIIIs-1; no woodland classification; Rough. Stony Land range site 10, all precipitation zones) 31 USE OF THE SOILS FOR CROPS AND PASTURE Grain sorghum, sorghum for silage, sweetpotatoes, tomatoes, sugarcane, and guineagrass are the princi- pal crops on the Virgin Islands. None are irrigat- ed. Crop response depends on adequate rainfall during the growing season. Complete fertilizer is. generally needed. The amount to be applied is best determined through soil tests. Crop residue management and applications of manure increase the supply of organic matter and help in controlling erosion. The capability grouping used by the Soil Conser- vation Service, in which the soils are grouped ac- cording to. their suitability for crops, is explained in the pages that follow, and suggested use and man- agement of the soils are described by capability unit. At the end of this section is a table that shows estimated. yields of specified crops on the soils now under cultivation. The soils in capability units Ile-2, IIs-1, IIc-1, IIIs-1, IIIs-2, [lIsc-1, IIIc-1, IVe-2, and IVc-1 would be well suited to irrigation if water were available. Capability Grouping Capability grouping shows, in a general. way, the suitability of soils for most kinds of field crops. The groups are made according to the limitations of the soils when used for field crops, the risk of damage when they are used, and the way they respond to treatment. The grouping does not take into ac- count major and generally expensive landforming that would change slope, depth, or other characteristics of the soils; does not take into consideration pos- sible but unlikely major reclamation projects; and does not apply to rice, cranberries, horticultural crops, or other crops requiring special management. Those familiar with the capability classification can infer from it much about the behavior of soils when used for other purposes, but this classifica- tion is not a substitute for interpretations de- signed to show suitability and limitations of groups ‘of soils for range, for forest trees, or for engi- neering. In the capability system, all kinds of soils are grouped at three levels: the capability class, the subclass, and the unit. These are discussed in the following paragraphs. CAPABILITY CLASSES, the broadest groups, are des- ignated ‘by Roman numerals I through VIII. The nu- merals indicate progressively greater limitations and narrower choices for practical use, defined as follows: Class I soils have few limitations that restrict their use. (There are no class I soils in the survey area.) Class II soils have moderate limitations. that re- duce the choice of.plants or that require mod- erate conservation practices, 32 Ciass III soils have severe limitations that re- duce the choice of plants, require special conservation practices, or both. Class IV soils have very severe limitations that reduce the choice of plants, require very careful management, or both. Class V soils are not likely to erode but have other limitations, impractical to remove, that limit their use largely to pasture or range, woodland, or wildlife habitat. (There are no class V soils in the survey area.) Class VI soils have severe limitations that make them generally unsuited to cultivation and limit their use largely to pasture or range, woodland, or wildlife habitat. Class VII soils have very severe limitations that make them unsuited to cultivation and that re- strict their use largely to pasture or range, woodland, or wildlife habitat. Class VIII soils and landforms have limitations that preclude their use for commercial plant production and restrict their use to recrea- tion, wildlife habitat, or water supply, or to esthetic purposes. CAPABILITY SUBCLASSES are soil groups within one class; they are designated by adding a small letter, e, W, S, or c,'to the class numeral, for example, Tle. The letter e shows that the main limitation is risk of erosion unless close-growing plant cover is maintained; w shows. that water in or on the soil in- terferes with ‘plant growth or cultivation (in some soils the wetness can be partly corrected by arti- ficial drainage); s shows that the soil is limited mainly because-it is shallow, droughty, or stony; and c, used. in only some parts of the United ‘States, shows that the chief limitation is climate that is too cold or too dry. For some soils'on the Virgin Islands, shallowness and climate are limitations of about equal importance, and the subclass symbol in- dicates both, for example, IIIsc-1. In class I there are no subclasses, because the soils of this class have few limitations. Class V can contain, at the most, only the subclasses indi- cated by w, s, and c, because the soils in class V aré subject to little or no erosion, though they have other limitations that restrict their use largely to pasture, range, woodland, wildlife habi- tat, or recreation. CAFABILITY UNITS are soil. groups within the sub- classes. The soils in one capability unit are enough alike to be suited to the same crops and pas- ture plants, to require similar management, and to have similar productivity and other responses to management. Thus, the capability unit is a conven- ient grouping for making many statements about man- agement of soils. Capability units’ are generally designated by adding an Arabic numeral to the sub- class symbol, for example, IIe-2 or IIIe-17 Thus, in one symbol, the Roman numeral designates the ca- pability class, or degree of limitation; the small letter indicates the subclass, or kind of limita- tion, as defined in the foregoing paragraphs; and the Arabic numeral specifically identifies the capabil- ity unit within each subclass. In the following pages the capability units on the Virgin Islands are described, and suggestions for the use and management of the soils are given, The names of the soil series represented are men- tioned in the description of each unit, but this does not mean that all the soils of a given series are in the unit. The capability unit designation for each soil in the survey area can.be found in the "Guide to Mapping Units." Capability Unit Ile-2 This unit consists of soils of the Glynn, Laval- lee, and Parasol series. These soils are on foot slopes, alluvial fans, and stream terraces. They are gently sloping, deep, well drained, neutral to slightly alkaline, and friable. The subsoil is clayey to loamy. Some areas are gravelly. The supply of plant nutrients and organic matter is high. Permeability is moderate, and the water- holding capacity is moderate to high. Suitable crops are sugarcane, tomatoes, and grain sorghum. Contour furrowing is needed if row crops are grown. The erosion hazard is moderate. Prac- tices that control erosion and provide additional organic matter are needed to preserve tilth. Droughtiness is a limitation during extended dry periods. No water is available for irrigation. Capability Unit IIs-1 The one soil in this unit, Fredensborg clay, 0 to 2 percent slopes, is a calcareous soil that is shal- low over porous marl or soft limestone. The surface layer is well supplied with plant nutrients and or- ganic matter. Runoff is slow, permeability is mod- erately slow, and the water-holding capacity is high. This soil is suited to sugarcane, tomatoes, Sweetpotatoes, and grain sorghum. It can be culti- vated within only a narrow range of moisture con- tent. When wet, it is sticky and plastic and is difficult to till. Preserving tilth and maintaining good structure are difficult. Droughtiness is likely to be a limitation during prolonged dry peri- ods. No water is available for irrigation. Capability Unit IIc-1 The one soil in this unit, San Anton clay loam, 0 to 3 percent slopes, is a deep, well-drained, fri- able, neutral to calcareous soil on flood plains and alluvial fans. Some areas are gravelly and sandy. Infiltration and permeability are moderate, and the water-holding capacity is moderate to high. The re- sponse to fertilization is good. This soil is. suited to tomatoes, sweetpotatoes, and grain sorghum. Generally it is in good tilth and is easy to work. Machinery can be used without difficulty. Artificial drainage is not required. There is no hazard of erosion. Lack of effective rainfall is the only limitation. No water is avail- able for irrigation. Capability Unit IIIe-1 This unit consists of soils of the Glynn, Para- sol, and San Anton series. These soils are on foot slopes, alluvial fans, and stream terraces. They are deep, well drained, neutral to slightly alka- line, friable, and moderately sloping. They are dominantly clayey in the subsoil. Small areas are sandy and gravelly. Infiltration is moderate, per- meability is moderate to moderately slow, and the water-holding capacity is moderate to high. The re- sponse to fertilization is good. These soils are fairly well suited to sugarcane, tomatoes, grain sorghum, and guineagrass. Gener- ally they are in good tilth-and are easy to work. They should be farmed on the contour. The erosion hazard is severe. Close-growing plants are needed to protect natural drainageways, and diversion ditches are needed to intercept and remove water that runs down from the steeper hillsides. Drought- iness is a limitation during prolonged dry periods. No water is available for irrigation. Capability Unit IIIs-1 The one soil in this unit, Fraternidad clay, 0 to 3 percent slopes, is a deep, moderately well : drained, neutral to slightly alkaline soil on allu- vial fans. The surface layer is friable to firm clay. It is underlain by firm clay. Fertility is high. Infiltration and permeability are slow. This soil is suited to tomatoes, grain sorghum, sorghum for silage, and guineagrass. It is diffi- cult to work and. can be tilled within only a narrow range of moisture content. It shrinks and cracks when dry and swells when wet. Machinery skids and sticks if the soil is wet. Shallow ditches are needed for good surface drainage. Capability Unit IIIs-2 The one soil in this unit, Fredensborg clay, 2 to 5 percent slopes, is calcareous and is shallow over soft limestone. It is well supplied with nutrients and organic matter. The response to fertilization is good. Runoff is medium, permeability is moder- ately slow, and the water-holding capacity is high. This soil is suited to tomatoes, sweetpotatoes, grain sorghum, and sorghum for silage. It is diffi- cult to work and can be tilled within only a narrow range of moisture content. The surface layer is sticky and plastic when wet. -Preserving tilth and maintaining good structure are difficult. Furrows should be on the contour if row crops are grown. The erosion hazard is moderate. Close-growing plants. are needed to protect natural drainageways, 33 and diversion ditches are needed to intercept and remove water that runs down from steeper hillsides. Droughtiness is a limitation during prolonged dry periods. No water is available for irrigation. Capability Unit IIIsc-1 This unit consists of soils of the Hesselberg and Sion series. These are nearly level to gently slop- ing, calcareous, friable clays and clay loams that are 10 to 20 inches deep over soft or hard lime- stone. They are well supplied with plant nutrients and organic matter. Generally the response to fer- tilization is good. Infiltration and permeability are moderate, and the water-holding capacity is low. Suitable crops are sugarcane, tomatoes, grain sorghum, sorghum for silage, and guineagrass. All plowing and furrowing should be on the contour if row crops are grown. There is no erosion hazard. The chief limitation is lack of effective rainfall. No water is available for irrigation. Capability Unit IIIc-1 The one soil in this unit, Coamo clay loam, 2 to 5 percent slopes, is a deep, well-drained, neutral to calcareous, friable soil on alluvial fans. Small areas are gravelly and sandy. Infiltration and per- meability are moderate, and the water-holding capac- ity is moderately high. The response to fertiliza- tion is good. Suitable crops are tomatoes, sweetpotatoes, grain sorghum, and guineagrass. All cultivation and fur- rowing should be done on the contour if row crops are grown. The erosion hazard is moderate. Lack of effective rainfall is the chief limitation. No water is available for irrigation. Capability Unit IVe-1 This unit consists of soils of the Aguilita, Pozo Blanco, and Sion series. These are gently sloping to moderately sloping, friable clay loams that are shallow over marl or soft limestone. Some areas have limestone outcrops, and some have limestone fragments on the surface. Fertility is moderate. Permeability and infiltration are moderately rapid, and the water-holding capacity is low. These soils are generally in fairly good tilth and are fairly easy to work, but they are not suited to cultivated crops. Sugarcane, for example, is damaged by chlorosis. Pasture of guineagrass and native grasses is probably the best use. Good pas- ture management is needed. The erosion hazard is severe unless the surface is protected. Generally, drainage is not needed. Droughtiness is a limita- tion during prolonged dry periods. Irrigation should not be considered; Capability Unit IVe-2 The one soil in this unit, Fraternidad clay, 3 to 12 percent slopes, eroded, is deep, moderately well 34 drained, gently sloping to moderately sloping, plas- tic, and calcareous. Sheet erosion has removed a large part of the surface layer. This soil takes in water slowly and releases it slowly to plants. Per- meability is slow. Fertility is high. Generally this soil is in poor tilth and is dif- ficult to work. It is difficult to till when wet, and it shrinks and cracks when dry. It can be cul- tivated within only a narrow range of moisture con- tent. Machinery skids and sticks if the soil is wet. Furrowing should be done on the contour if cultivated crops are grown. Irrigation is bene- ficial. Capability Unit IVe-3 This unit consists of soils of the Jacana series. These are gently sloping to moderately sloping, well-drained, neutral to slightly alkaline soils on foot slopes. They are moderately deep over volcanic rocks. The surface layer is friable clay loam. In- filtration and permeability are moderately slow, and the water-holding capacity is moderately high. Fer- tility is high. The response to fertilization is good. These soils are well suited to guineagrass and native grasses and are fairly well suited to sugar- cane. Generally they are in poor tilth and are dif- ficult to work. Any cultivation should be shallow. It should be done on the contour and at optimum moisture content. If areas in pasture are to be used for cultivated crops, natural drainageways should be left in grass and used as protected out- lets. The erosion hazard is severe unless the sur- face is protected by a grass cover or erosion is controlled by some other conservation practice. Good pasture management is needed, especially during dry periods when grass is semidormant. Crop re- sponse depends on adequate rainfall during the grow- ing season. Stands of planted crops are likely to be poor. Capability Unit IVe-4 The one soil in this unit, Fredensborg clay, 5 to 12 percent slopes, eroded, is on foot slopes. It is calcareous and is moderately deep over soft lime- stone. Runoff is moderately rapid, infiltration and permeability are moderately slow, and the water- holding capacity is high. Fertility is high. The response to fertilization is good. Generally this soil is in poor tilth. It can be worked within only a narrow range of moisture con- tent. The surface layer is sticky and plastic when wet, and tillage is difficult. Preserving tilth and maintaining good structure are difficult. All cul- tivation should be on the contour. If areas in pas- ture are to be used for cultivated crops, natural drainageways should be left in grass and used as protected outlets. The erosion hazard is severe unless the surface is protected by close-growing plants or erosion is controlled by some other con- servation practice. Good pasture management is needed, especially during dry periods when grass is semidormant. Crop response depends on adequate rainfall during the growing season. No water is available for irrigation. Capability Unit IVw-1 The one soil in this unit, Aguirre clay, 0 to 2 percent slopes, is on the coastal plain. It is deep, poorly drained, and calcareous. The surface layer is friable to very firm clay. It is underlain by firm, sticky, plastic clay. Infiltration and permeability are slow, Natural fertility is moder- ate to high. This soil is well suited to malojillograss or paragrass but is poorly suited to sugarcane and other cultivated crops. Generally it is in poor tilth and is difficult to work. It can be culti- vated within only a narrow range of moisture con- tent. The clay shrinks and cracks when dry and swells when wet. Machinery skids, slips, and sticks easily if the soil is wet. Poor drainage, the high clay content, and in some areas, the alkali make tillage and crop production difficult. Grazing ani- mals should be kept off wet pasture because they de- stroy the grass by trampling. Open ditches are needed for surface drainage. Installing subsurface drainage is difficult because of the position of this soil on the landscape, the slow permeability, and an intermittently high water table. Capability Unit IVc-1 The one soil in this unit, Cornhill gravelly clay loam, 0 to 2 percent slopes, is a deep soil on allu- vial fans. The surface layer is gravelly clay loam that is friable when moist and brittle and hard when dry. The subsoil is heavy, plastic, sticky, calcar- eous clay that shrinks and cracks when dry. Infil- tration and permeability are moderate in the surface layer and slow in the subsoil. Natural fertility is moderately high. This soil contains much gravel. It is generally in poor tilth and is difficult to work. Stands of planted crops are likely to be poor. Most of the acreage is pasture. Good pasture management is needed. Grazing should be deferred to permit grasses to reseed. Lack of effective rainfall is a severe limitation. Drainage is no problem. No water is available for irrigation. Capability Unit VIe-1 This unit consists of soils of the Cramer, Doro- thea, Isaac, Jacana, and Victory series. These soils are moderately sloping to steep and are moder- ately deep to deep over volcanic rocks. The soil material is friable. Some areas have scattered rock fragments at or near the surface. Infiltration and permeability are moderate to moderately slow. Natural fertility is moderate. These soils are well suited to guineagrass and native grasses. They are difficult to work bécause of the gravelly surface layer, and they should not be cultivated because of the slope and the risk of erosion. If areas in pasture are to be used for cultivated crops, they should be cultivated on the contour and natural drainageways should be left in grass. The erosion hazard is severe unless the surface is protected by permanent vegetation. Pas- ture management is needed, especially during dry periods when the grass is semidormant. Grazing should be controlled or deferred to permit grasses to reseed. Irrigation should not be considered. Capability Unit VIe-2 The one soil in this unit, Magens silty clay loam, 30 to 50 percent slopes, is on mountainsides. This is a red, friable, acid, clayey soil that is deep over very highly altered material mixed with a few volcanic boulders. Infiltration and permeabil- ity are moderate, and the water-holding capacity is high. Fertility is moderately low. The response to fertilization is good. This soil is easy to work, but the slope and the risk of erosion severely limit its use for culti- vated crops. If areas in pasture are cultivated, they should be planted on the contour and natural drainageways should be kept in grass and used as protected outlets. The erosion hazard is very se- vere unless the surface is protected by a grass cover or erosion is controlled by some other conser- vation practice. Pasture management is needed, es- pecially during dry periods when grass is semidor- mant. Grazing should be controlled or deferred to permit grasses to reseed. Irrigation should not be considered. Capability Unit VIe-3 This unit consists of soils of the Aguilita and Pozo Blanco series. These are alkaline, sloping and strongly sloping, well-drained soils on uplands. They are shallow over soft limestone or other limy material. The surface layer is gravelly clay loam. Infiltration and permeability are moderate to rapid, and the water-holding capacity is low. Natural fer- tility is moderate. These soils are well suited to guineagrass and Native grasses. They are generally in fairly good tilth, but they are difficult to work and are sus- ceptible to erosion. Stoniness and shallowness preclude cultivation. Most of the acreage is in pasture. Pasture management that promotes maximum growth of the best grasses is needed. Much of the acreage in brush could be cleared and seeded to suitable grasses. Irrigation should not be con- sidered. Capability Unit VIs-2 This unit consists of Diamond soils and Limestone rock land. The soils are-nearly level to moderately 35 sloping, well-drained, friable, red clay loams that are very shallow over hard limestone. Limestone outcrops make up about 50 percent of the acreage. Infiltration and permeability are moderate to rapid, and the water-holding capacity is low. Natural fer- tility is medium. ; These soils are well suited to guineagrass and native grasses. They are generally in fairly good tilth, but they are difficult to work. The shallow- ness and the outcrops preclude cultivation. Pasture management that promotes maximum growth of the best grasses is needed. Much of the acreage in brush could be cleared and seeded to suitable grasses. Irrigation should not be considered. Capability unit VIs-3 This unit consists of soils of the Cramer, Des- calabrado, and Southgate series. These soils are on mountainsides. They are moderately sloping to mod- erately steep, are well drained, and are less than 20 inches deep over volcanic rocks. Rock outcrops are common. The surface layer is friable clay loam or gravelly clay loam. Runoff is excessive, infil- tration and permeability are moderate to moderately slow, and the water-holding capacity is low. Natu- ral fertility is moderate. These soils are fairly well suited to guineagrass and native grasses. They are not suited to culti- vated crops. They are difficult to work because they are steep, shallow, and in. places gravelly. Any cultivation should be done on the contour. Most of the acreage is in pasture and brush. Only a small part is cultivated. Many areas now in brush could be cleared and used for pasture. Pasture manage- ment is needed. The number of animals grazed should be reduced during dry periods. Droughtiness is a severe limitation. Irrigation should not be con- sidered. Capability Unit VIIe-1 This unit consists of soils of the Aguilita se- ries. These are steep and very steep, well-drained, alkaline gravelly clay loams that are very shallow over soft limestone. They hold only a small amount of water that is available to plants. There are rock outcrops and many limestone fragments on the surface. Infiltration and permeability are moderate to rapid. Natural fertility is moderate. These soils are generally in fairly good tilth but are difficult to work because they are steep, stony, and shallow. They are well suited to guinea- grass and fairly well suited to native grasses, Most of the acreage is in pasture and brush. Pas- ture management should promote growth of the best plants, prevent loss of stands, and permit plants to reseed. The acreage in brush could be cleared and seeded to grass. Much of it would make good pasture. Erosion is a hazard unless a permanent grass cover is maintained. Irrigation should not be considered. 36 Capability Unit VIIe-2 The one soil in this unit, Dorothea clay loam, 40 to 60 percent slopes, is on mountainsides. It is a friable, neutral to slightly acid soil that is mod- erately deep to deep over altered volcanic rocks. Runoff is rapid, infiltration and permeability are moderate, and the water-holding capacity is high. Natural fertility is moderate. This soil is well suited to guineagrass and na- tive grasses. It is difficult to work because of the slope and consequently is not suited to culti- vated crops. The erosion hazard is very severe unless the surface is protected by permanent vege- tation. Pasture management is needed, especially during dry periods when the grass is semidormant. Grazing should be controlled and deferred to allow grasses to reseed. Irrigation should not be con- sidered. Capability Unit VIIs-1 This unit consists of soils of the Cramer series. These are steep, friable soils that are less than 20 inches deep over volcanic rocks. From 50 to 70 per- cent of the surface is covered with stones 1 to 3 feet in diameter. Runoff is excessive, infiltration and permeability are moderate, and the water-holding capacity is low. Natural fertility is moderate. These soils are suited to guineagrass and native grasses. The slope, stoniness, and shallowness pre- clude cultivation. The erosion hazard is severe un- less the surface is protected by permanent vegeta- tion. Pasture management is needed, especially during periods when the grass is semidormant. ing should be controlled and deferred to allow grasses to reseed. Droughtiness is a limitation. Irrigation should not be considered. Graz- Capability Unit VIIs-2 The one soil in this unit, Jaucas sand, 0 to 5 percent slopes, is adjacent to the sea and just above high tide. It is a deep, light-colored, cal- careous, loose sand that contains many fragments of coral and seashells. It holds only a small amount of water available to plants. Drainage is excesSive, and infiltration and permeability are very rapid. Natural fertility is low. This soil is generally in good tilth and is easy to work at any moisture content. It is well suited to coconuts and seagrapes. It is somewhat poorly suited to guineagrass and native grasses. It is not suited to cultivated crops. Some areas are planted to coconuts, some are in brush, and those sprayed by sea water are barren. Irrigation should not be con- sidered. Capability Unit VIIs-3 This unit consists of soils of the Cramer, Des- calabrado, and Southgate series and areas of rock land. The soils are very steep, friable, and clayey and are very shallow over igneous rocks. Rock out- crops are common, and there are many rock fragments on the surface. Runoff is excessive, infiltration and permeability are moderate, and the water-holding capacity is low. Natural fertility is moderate. If well managed, these soils are fairly well suited to guineagrass and native grasses. The slope, shallowness, and rockiness preclude cultiva- tion. surface is protected by permanent vegetation. Most of the acreage is in pasture and brush. Pasture management is needed. The number of animals grazed should be reduced during dry periods when the grass is semidormant, and grazing should be deferred. to permit grasses to reseed. Many areas now in brush could be cleared and used for pasture. Droughtiness is a limitation. Irrigation should not be consid- ered. Capability Unit VIIs-4 This unit consists only of Cobbly alluvial land. This land type is on the islands of St. John and St. Thomas. It occurs as gently sloping to moderately sloping, narrow strips close to intermittent streams, and it is subject to flooding. The texture varies. Subangular and subrounded, very hard vol- canic cobblestones make up 59 to 75 percent of the soil mass. Infiltration and permeability are rapid, and the water-holding capacity is low. Poor workability, the overflow hazard, rapid per- meability, and stoniness preclude cultivation. Most of the acreage is in pasture and brush. Guineagrass and native grasses grow fairly well if pasture is well managed. The number of animals grazed should be reduced during dry periods when the grass is semidormant, and grazing should be deferred to allow plants to reseed. Many areas now in brush could be cleared and used as pasture. Irrigation should not be considered. Capability Unit VIIIw-1 This unit consists of inundated swamps and flats in the coastal lowlands near the sea. These land types either are under sea water or are flooded during high tide. When the flats are not inundated by high tide, the water table is near the surface. In most places the surface is covered with a thin salt crust. The soil material consists of light- colored, saline, strongly alkaline sand and clay. Natural fertility is low. These land types are of no value for farming. The swamps support mangrove trees. They are fished for oysters and are used as recreational areas. The flats support only salt-tolerant weeds and grasses. Much of the acreage is barren. None of it is grazed by livestock. Capability Unit VIIIs-1 This unit consists of land types that have no po- tential for cultivated crops, grasses, or trees. The erosion hazard is very severe unless the These land types range from nearly level to steep. All are rocky and shallow. There is very little soil material. Some areas have been reworked and leveled in cut and fill operations. Others have been filled with sandy material dredged from the bottom of the sea. Estimated Yields Estimated yields of the principal crops grown on the Virgin Islands, under two levels of management, are shown in table 2. The“estimates are for the soils now under cultivation. They are based on rec- ords kept at experiment stations, on information obtained from farmers, and on records compiled by agronomists who have had experience with crops and soils on the islands. The yields are those obtained during periods of average rainfall. During wet per- iods, yields are likely to be higher than those shown in table 2, and during unusually dry periods, they are likely to be much lower. The A columns in table 2 show the yields that can be expected under average management. The B columns show the yields that can be expected under improved management. Improved management provides -- fa) Complete fertilization according to the re- sults of soil tests. . Adequate seedbed preparation. Drainage and water control if needed. Planting of proven varieties. Cultivation at proper range of moisture con- tent and to the proper depth. 6. Control of weeds, pests, and plant diseases. 7. Harvesting of crops at the proper time. 8. Management of crop residue. No burning of residue. 9. Protection from overgrazing. 10. Establishment of erosion control practices. Wb WN None of the crops grown on the islands are irri- gated. Crop response varies according to the amount of effective rainfall during the growing season. September or October is the most favorable time for planting. Some crops that are not produced commercially were planted at the Agricultural Research Service Experiment Station on Fredensborg clay, 2 to 5 per- cent slopes. The yields obtained under improved Management were-- Corn for silage: in two crops. Elephantgrass: 40 tons per acre, in three cut- tings, using 250 pounds of nitrogen per acre. Corn for grain, St. Croix Long Ear variety: 1,800 pounds per acre. Yams, Sealtop variety (Discorea): 20 tons per acre, green weight, 12 tons per acre. Cassava: 15 tons per acre, in a 9-month period. Bananas: 50 hundredweights per acre. Planted 4 feet apart both ways. String beans: 12,000 pounds per acre. 37 umy uter5 $9028 0dqaemS soo}ZeWO]L Seemesaces Ssesecesee sedo[s jusored Z] 02 S ‘weOT AeTO UOTS See e cee cseS eto ease sodots qusozed ¢ 03 go ‘weot AeTS UOCTS waee----------- sedo[s Juad1ed ZI 02 ¢ “weoT ABT uoqUy URS eeeeeecetscosss sodojs yusozed ¢ 023 Q ‘uweoy AeTS uoqUy UES Sareea ~-sedoTs quaozed z~ 02 ¢ ‘weoT ABT ooURTg 0z0q eee ae ee ee eee sedots queozed ZT 03 ¢ ‘weor Aeto Tosezeg Soo2 sectee ase aeae sedo[s jueszed ¢ 02 Zz ‘weot AeTD Tosereg woe een- sedo[s qusdxsed ¢ 02 Zz ‘weoy ABT AT [AAeAB vaT[eAeT on------ sado[ts yuac1sd Z{ 02 ¢ ‘ureoyT AeTO euRser --sedots queozed ¢ 02 Z ‘ureoT AeTO eueser pOeeecee sie osene ~---sado[s queorsd z 03 g ‘AeTo BzoqTassay See esaseoes popors ‘sadoys yusored z~ 01 ¢ ‘weoT AeTd UUATD epee eee ee sedots queozed ¢ 03 2 ‘weoT Aeqo uudT) w--------- pepote ‘sadots queored Z71 02 ¢ ‘ABTS B1oqsuapery ween e nee nnn eenne- sedo[s quaszed ¢ 03 Z ‘Aelo B10qsuepery Ueewesescesssee see sado[s quaszed z 02 9 ‘Ae{o Bx0qsuapary wee ee ne eee pepote ‘sado[s 3uaszed z{ 03 ¢ ‘AED peptuseqeay Seaspermeee cosas sedots yusored ¢ 03 9 ‘AeI> peptusezeay ee sedoTs jusozed Zz 01 g ‘weoyt ABT ATTeAeIB [TTTYUIOD Beceeceessecseeeacas sedots jusozed ¢g 02 2 ‘ueo, Aeqto oweo Re ee ---sado[Ts quaozed Zz 01 9 ‘AeTO aszTn3y ees sedots queozed ¢ 02 z ‘ueot Alto ATTeaeas eqrypinsy Tt0s [2uoweseuew poaordwt repun spots E g SUUNTOD UT SeINsTZ ‘juowedeueM sdeIeae TapuN spTeTA oeoTput y suumyod ut sein3ty]} SO STSAXT OML UAGNN SdOWD TVdIINTUd AO TWOV Udd SATHIA JOVYAAV GALVWIISA--*2 J TaVL 38 Cucumbers: 6,000 pounds per acre. Pineapple, Red Spanish variety: 21,500 pounds per acre. Fruits were 3 to 4 pounds each. Papaya: 10 tons of marketable fruit, 15 tons total fruit, per acre. USE OF THE SOILS FOR SHADE AND FRUIT TREES, SHRUBS, AND ORNAMENTALS“ Tables 3 and 4 show the suitability of many plants for specified soils on the islands. Among these plants are shade trees, fruit trees, and trees and shrubs that are decorative and are used as ornamen- tals. None are produced commercially. Table 3 is for St. Croix, -and table 4 is for St. Thomas and St. John. USE OF THE SOILS Grassland on the Virgin Islands amounts to almost 25,000 acres. Most likely, much of the acreage for- merly in sugarcane will revert or be converted to grassland. Production of beef cattle, predominantly the Senapol breed, is the chief source of farm in- come. The soils used as range are mainly the deep clays and clay loams on the coastal plain and on flood plains, foot slopes, and low hills, and the shallow clays on side slopes. Most of these soils are fer- tile. Their suitability for rangeland is limited mainly by lack of sufficient rainfall. Range Sites and Condition Classes Different kinds of soils produce different kinds of grass and other vegetation. The soils that have similar climatic and physiographic features and that produce about the same kinds of plants and about equal yields of forage are grouped together for range management purposes. These groups are called range sites. Each range site has its own distinc- tive potential for producing native plants and re- tains its ability to reproduce this plant community unless the soils are materially altered or have de- teriorated. Range condition is determined mainly by comparing the kinds and numbers of plants that make up the vegetative cover with those in the potential native plant cover, or climax vegetation, for the same site. Climax vegetation, or potential native plant cover, is the stabilized plant community on a par- ticular site. It reproduces itself and does not change so long as the environment remains’ unchanged. Decreasers are plants in the climax vegetation that tend to decrease if heavily grazed. These plants generally are the tallest, most productive, and most palatable perennials. Increasers are plants in the climax vegetation that normally increase as the de- creasers decrease. These plants commonly are the shorter, less productive, less palatable plants. 2Ry Richard M. Bond and Axel Fredericksen, Agri- cultural Research Service, Agricultural Experiment Station, Kingshill, St. Croix. Many of these plants are well suited. Some can be establihhed under special management. Others, particularly ornamentals, can be established in holes, trenches, and garden beds that are filled with suitable soil material. FOR RANGE Invaders are plants that are not part of the climax vegetation but that become established after the climax vegetation has been heavily grazed. Many in- vaders are woody plants. They may originate nearby or at a great distance. Range condition indicates the degree to which the composition of the existing plant community differs from the climax vegetation. Four classes are recog- nized. A range is in excellent condition if 76 to 100 percent of the vegetation is the same kind as that in the original stand; it is in good condition if the percentage is between 51 and 75; in fair con- dition if the percentage is between 26 and 50; and in poor condition if the percentage is 25 or less. The changes in the plant cover may be of a perma- nent or temporary nature. If management is good and there has been no soil deterioration, rapid recovery to the original climax cover can be expected. If the soil has deteriorated, from trampling or from erosion, recovery is much slower. Descriptions of Range Sites The 11 range sites recognized on the islands are described in the following pages. Each site de- scription gives estimates of the total annual yield of air-dried forage, per acre, on a site in excel- lent condition. The soil series represented are named in the description of each site, but this does not mean that all the soils of a given series are in the site. 1. Deep Range Site (4S to 60 inches precipitation) This site occurs mostly at the base of hills, along stream terraces, and on alluvial fans. It consists of soils of the Coamo, Glynn, Lavallee, and San Anton series. These are clay loams that are more than 20 inches deep. This site is very well suited to guineagrass and pangolagrass. If ovérgrazed, these grasses are re- placed by hurricanegrass and Barbados sourgrass. Brush invades as range condition becomes poorer. 39 TABLE 3.--SUITABILITY OF FRUIT TREES, SHADE TREES, EXOTICS, AND ORNAMENTALS FOR SPECIFIED SOILS ON ST. CROIX ; figure 2 indicates that it is suited under at the plant is not suited] special management; figure 3 indicates th [Figure 1 indicates that the plant is suited to the soil Soils weoT AeTo ALODTIA| NKR AHNNR AN RR ANNAN tt NNN INN weoyt AeTD .o7eSyyNOS RN HHA AAEM AER ANN NANA AR HNMR weoT ABTD WTS | ANN HHA RH ANN TRAN ANAS ANAM NNN ANT AMMAN ANAINNN weoT ABTD TOSBIEG| NARA R RHA NRTA NN ANN tN puel FOOL suozssuly] MMMAMMMMM MAM MMMM MM MAMMAMMMMMANMMAM MMM mM weoy, AeTD A[TeAels saTTRART | NARA RNR ANN INN Nt NINN Pues SBONEC| MN HANMAMDAMAN RAN MATANANAMAMAMMAMNANM AN MAN weot Aelo eueser HAH FHA NSB HN RRR ARTF NMBA NT HTT N NIN SS weo, AeTo A[TeAeIZ: Dees] AA MAAN AR EMER ANN NNR RR ANN NER NN NGA ABD BLOQTessoy MM MAMMMAMMANMMMMAAAANMAMNANAAAAMM AMMAN weot AeqTo uukT9) NAN HMNNNMANANAMA RAR NANG NANT NAN NA NNT NAN NNN keto BLoqsuepelgy NAAN TARR AMN FRAN MANN RANMA NHN TIAN NNN Aelo peptusrezery ANNAN MANNHANANANANNTE NNN ANA MAT N AN TAN TM NAM weo,T ABO Ppucue4rg BM MMM MMAR AMM MM MN AANA MMA MMM MAN AMMAN MMMM MH wWeot kero operqeTeosag ABH HAHN NN DR RN AN NN weot sep. Auo s qewer) cs 2H i wea AA a See Ae oe ee a weot AeTo ATTeAer3 IsueLD NAN NE RAN RR RN AA weoy ABTo AT[9AeIB. [TT TYyULoD NHN ANNAN TMANNMAMN BA ANTANNANN NN GHD AN ANAM AMNM weot AeTS oweo) NHAFAN HAMANN SHAMAN BARRA ANA NANG NN INN ABD VILINBY| NNN NMANNAMAANAMAMAANAAANAANAANMANANAN ANAM ANA weo, AepTo ATT@ABIZ BITTINIV| MMANANNAMMANMAMNA DANA N AN MAMMA TAN M ANAM NI grapefruit-------------------- Plums de Terre--~--------- 2-37 ence nnn Avocad0----------- 9+ -- 7 nner nner nnn} 1b Ut $obopett!eoto bot ro 1 1b oF Lt tod Fa. eee ae tt | ee reope pe ee ee OS peaod nr teopeet to pa tb tee bt tet te ee a res aed Pe ee ee ee OO OO en | yonota Ce Se en OO oped peed 1boeteoedabooeebt bdo ¢ © t bP be be et a ea rr ee | aed Cs ee | | Te ae | 1 bot 1aer6bopet@# 6 @ t 9 'osed t+ 8 -b oF tpt peoerat td @ bo oe tot ot 6 be oF be ek be tb a a 'obeto nn a ee ee ee “)houebto nn ne aroterrete# @ te bt t t to PO PoP be a te bob bbe oe en ee | Pode toa t be oe ag bet ot bob ad FF ob be ba en ee aps i ee ae ee opto tobst 1aiebtattetopeuee tod to b 8 bea ha pods poaroea Pe ee ee OO ae en | nn iaeoperteere bobo eb 8 # Fob bt ob be db te hoot yn ere re De ee ee SO pore 2 on (poeet rer ebt ber oot bob be bt bob to bt bb ta robot i= ape tte teh toe ke 8 8 bd he ee nn 8 1a Ce ee ee pooe — Bobo rs er ee | | tt 6 toeopweopet @ 6 6 6 t £ 8 8 [| a top toboeoetvo ret to aoa 46 | ot 1b ates Te ee ee eS poe aoe nr on 1@ittenrtoe ft t bet tobe t tt tb bobo oboe tb! boo ees tees 1reme®e Ce ee Oe otouwad 1aeg (mt ted to Ft ea Ot ee t you Oe ‘ge! ee ee ee en pease mt ters 1weeodtisdareit@ditrwenanit ote re ee ee ee ee | ee | dott fy reo r ree 1 ore i gy be at oud’ bo tot et opera ate ’ a1 Oe tie tw r1reBrsmivprr grip etovees 1rt@o S186 Poa 1 og ' wi eo Ommt at tee ttt ia ee en rd Prt es l&eded § OM t Gt GE t wit 16 Batuea bag 41 Od SB ted ! > tw a ee ee eet Home Ott wee Ft Pirie & Read 1 oag iww igs nhs POPS Lt at i g£Sods BS eva Ot AH = SAEH' Oat ROoE LSS eoiecgi st Ovpvos Ss DH ea CH oe teVOHEAOA! Og MALO DO Ss BHANO 1 DHOOM & WE SD OO ‘A oe Axe age COOP OER Fed bon 0 = Peo Beeaeoewass aso o fy Ew Bseeugessess SsSenreoraeg a SESE RGR OES REE Weaiads OQHRDODHNASAHAHOAHOOS SA OV Sexo Da Hey Bex Oo qaeane RAAMUUUUVUOUOAREBUVOUOOTIHHANVASSZSZOOOaHRM weoT AWD UOWY UPS) AH HAN RRR NR NN NNN NS 40 Soils weoy AeTo e7esYINOS HANNAN AN Maa weoT ABD UuoTs NANN FAs Ss weot Ae[D uoquy ues HH ddA aA AN weot Ae. Toseieg SHAN eta puel YOOT suo SeUTT | wpmmnMnMnnMnmnm weoy Aet> ATTSAPTS P2ETTRPART | GaN nena pues seonerl | nammnmmMmamn weot AeTO euesee | oa aaa: weoT Ae[o AT[eaers Ves] NAN SAMA ARAN A€TD B1AqTESS9H | mammaMaAamn weoyT ABlo uUuATD ANNN ANAM kel. Bzroqsusperj ANNAN FN ASS et AeqT) pepture ery NANNTAN NAN N weot ABTS puoueTd | mmmnmamm am mo weoyT ABTS operqeTeosed | ana aH AMaAN weot Aeto Auoqs towetlg | uN HAN MAM weo,T AelT> ATTeaesis Lowery ANA AN MAAN weoT Aes ATTAABIZS TITYUIOD | anamqHANANANAN weoT A®TD OOD LP aN ANNAN weo, Aepo AT[SeAeIZ BYTITINsy 41 TABLE 3.--SUITABILITY OF FRUIT TREES, SHADE TREES, EXOTICS, AND ORNAMENTALS FOR SPECIFIED SOILS ON ST.. CROIX--CONTINUED Plants ios 16 iso oo aot to toe | oo ie +4 1ot 18 oo 4 0 1g 14 to 18 too ot on 1 oo 4 ‘or ot ot Lot el ai 28 a sh Se fom) ay ' fl I ' f | i ' I ' f ' 1 1 1 ' 1 i ( ' f 1 1 ' ' ' i ' ! ( 1 i i=] 2 I fo] wn ‘ t a ' ' t ' ' ‘ ' ' ' f ’ i ' ' ' 4 ‘ ' ' i 1 ‘ t l t o = a i) ba] 9] ot n 1 i i 1 f 1 1 1 ‘ ' 1 t 1 ' ! ’ ' ’ ' ’ ' 1 i ' 1 1 ' ' ' t uo) is od by : a ' ‘ 1 i} t: i] J ‘ 1 ' i] t ' 4 ' ' 4 i] i) i} ] i t ' ' i) i] i i} 1 t 1 1 3 4 Ee Teak---------------------------------- Turpentine-myrtle--------------------- West Indian cherry-------------------- Vatiees ooo ncee secon te cede cebeteeee suited to the soil; figure 2 indicates that it is suited under Soils figure 3 indicates that the plant is not suited] SOILS ON ST. THOMAS AND ST. JOHN TABLE 4.--SUITABILITY OF FRUIT TREES, SHADE TREES, EXOTICS, AND ORNAMENTALS FOR SPECIFIED special management ; [Figure 1 indicates that the plant is WEOT ABTS ALOJIIA | NAAANNA RNR RSNA NNN NINN INS weot Aez{D 97e3yY3Nn0¢g AN HANAN AMAR ANNAN ANN NM weot Ae uoqyUuy ues HHH AN HRN ARH NHN HH NRT N RMN weot Aeqto OOURTYG 020g NM HAH ANNTR NNR AMAMA RAB HANNAN MANAN TANNA NN AON weot feo AVIS suesey SHAH AHN TRA A KH HR NN BP AND TARR NA NAT NN BR HATA N ATR N GTN PueT YDOI sUu0zSeUITT] AM ite ae eee i OO mee mune mon WeOT Aeqo ATTAeAeI3 SOT [PART NAPA AN TR AN FH AAA AN GRANT RAAT NTA TAAAN MAN TANN SS pues seoner MN ANMAMNA MAN FAN MNTANANAMNAMAMMAMANMANAMANMMM weo{ AeqTo AT[eAeIB DeeST NN AAN NFA MHRA NNN N DP DA ANN GN TAN AN HHH NDA NNN weot keto uudT NANUNAMANN MAN NAN MN DAPI N MND NN DR HAND ANN ANNAN wWeOoT: Aeqto Beoyyzo10g BHNAN HANH HH NDA NN BHR RR RR RH NAHM N NNN WEOT kejo Auojs lowe19 AHNNANN ANN FAM DN MAH HDR ATR PRAM N TNR RAN ANN Tt weot AeTo ATToeaeas Lower) HHNN FAN RH AN ANN TDR A ADIT NATHAN AN HHH HANNS et weort Aejo AT Teaes3 BTL Indy NAUNNNRAMMANMA MA FANT NANNNANMAM MARE NMA AMMAN MMM a OD OD pee t apt # o toe bo top be § Poe bab tb ee te bt tbe ee tte ‘ i) 1 1 i] i] i 1 i] iC t ! . ' ' a ' 1 U ' ' i ' i 1 t ' i) i i ' ' 1 1 t ' 1 i 1 i ' i) 1 t 1 ' ' ' 1 4 i) 1 1, ' i ' 1 ' t i) i] 4 t ' i 1 i ’ 1 v 1 ' ' i 1 ' ! ', i] ' ' i) ' t ' ' 1 1 i] i) ' ' , i ! ' ' ' a 1 i] £ ', ' iT 1 i] 1 1 i 1 1 1 1 2 i] ! i] ! 1 oro e# poet to topo pe t bo bobo tb bob tb be ba at a a tt yorodeotouopea 6 t bo pet ft to boo Ff to bob bob Foe de bbe te Ce ee OS J i) ' ' ' i] ' J 1 ' i] ' ' I 1 LT ' ' = i 1 iT ' 1 1 t 1 1 ' ' 1 1 i] ' i] ' ' ' i] ' 1 ‘ ' 1 1 1 t i ' 1 i] t ' ' ' i i. ! ' i} t ' i i] ! ' 1 1 ' \ 1 ' t i) ' 1 i} t i] ' i t 1 ' i oa ' 4 i] 1 4 1 t 1 t i] i 1 1 ' i] + 1 i] 1 i] { i) ' ! \ i] 1 ' 1 i} ! ' i oer ad @ bopeae to tb ob to t bo bb bb ee a ek a a reob ep a@ bt # bot po bob ft tot bt eb ee be a te at 'oaouedaddoaetopeoyet eo bot ot t top tf bob bob bb hoa te ta he tt oe bk of <* ' i] V ' 1 i ! ' ' ' 1 1 i) J t ' 1 if i] t i} i] L t t i) 1 ' i) 1 ' ' t yf ’ i) ' t 1 3 5 1 i ' 1 ' § ' i ' i] ' i} i] ' 1 i] + ' t 1 1 ’ t t ' i 1 i ' i) 1 1 t pooeott bo vonpeg a t 8 b t a 8 bt bo bot bb a te tet eb a roretaetoe se t es be et eb bb et be ea tt n 1troeptoe se to pea tet ret toe Fob tb bb be tte et a et a a v Ce Ss 1 t ' i] 1 t i 1 Ly v ‘ ' ‘ t 1 i 1 ' 1 1 ' i] i I 4 ' t i) t ' i) 1 1 ' 1 1 t 1 t i 3 ' i) ' i] t 1 i] ' t i) 1 ’ 1 ' 1 1 v 1 1 1 [3 $ Is 1 t 1 i ! 1 1 ' 1 1 1 ' 1 1 1 1 1 4 toto! do poe ft # t tf bo bt tot te tot ob tb be tb a ee te a at a, topo eovebt @opet a bo bop oe tf bot ob tb) bt bb ae at oooe Ft opeb tb oe ob at be tt ob bt kt a a et at Ce ee CO OC > #opo' Or berg et top tee ee to bp tt toe be bb bop eb Et be eh be tb ee Rb bd oobor gs top os tt bed tb ob bP ob te Deer Fo eo t Oe ' SG por bt toys 1G tf £ tf ¢ @ Or tem t tw we@top Bett pt oe Vo et moro to be bb ot DO t Fob fe teri mt!)ewreggrigogkiwoiw tire 1&6? Ov te ott t frot rou & aris 1) Oe bt Ot tare t tt Btwetwpesepeseen1pvvqemseopvpo+;eove SirvVreirne her inawkgi tt MtreeuA tr OnNRt?ENA! FF et t!tpetts fee tT we Plot Gi t Aedert 1 OMt 1 At Ee Huns £ eb Bt be ot 8 ok Oe I OS GB tert i 4 Pai ev Gs SS we te Me Ot tweeted vy re co eSedienor «eet wn (wohrnat Po eee ht IS tee BEY SEU SUV O BH F Bex eouwi ont anoeri od eooi1nvetsi ovuyvors ds Cw VBEHROKRKBVOHEROWi anwmavdvoaetaBnano! BANOS BIAS ON ee a ee > | S.0 25 ta EW@GRe sz 2 eyes e 2a GPeRESPSC OSE OES Re OCS ee Wee BD SO SDBOOOH BBH HOH OO SB BHA OW BA Seshseaed C€e€{#{eCtq@qNMNANMNoOVUVGCVCOCALLOUVOVIGOODTIWAVASZS zoooqaaand 42 weoT Aeq{d AIOWTA HANNAN Ade WeOT ABTO AT TeAei3 sel [BACT | wea | weoy Aerts ATTeAeIS DEST aannamanas | weoyT AeTo eay.o10g eines ecoeiceers, weoT Aeqto Auo Vs Lawes meena oe | weol AeTo AT Teaes3 zeues | an anamnce | TABLE 4,--SUITABILITY OF FRUIT TREES, SHADE TREES, EXOTICS, AND ORNAMENTALS FOR SPECIFIED SOILS ON ST. THOMAS AND ST. JOHN--CONTINUED a4 weo, Aelo A[[eAeis el iInsy MANN AN PANE Dopeoroyetououpou i) Oe ay OP as i] root topet to potog toed peed t to horoto topetii pout I ' ot Fo po bpoprotuo € 1oboettt @t donoue yoboeopoeo bot topo Poreador ¢ bt tote toe porebtotote to pot patrpepttepet Popopd toy topo | prerroerbaet!rs poroeudbopes gt tee toeoprherep to pout 'tpauebpopeset tbr Pe be 4 roropep¢ € t tet pppoe topet tot toortopreerbovpeage ye he a Le 1 fe ee | i) ttterypeohn to ¢ b bot tot hs prrerrrire ot (opeprdopesd oa! ioperpptt rao pret t to & ’ t toeopeop bout w@ie B&2;11o1set Ow at bet bt Sew ASABE! EE | roa 1 eOod-eeH 1 1 oe I anny h oI o t eo OH AD ASK BY 1 esSeaPeagsaasg ooosn wot oO ZNNNREP RRR S> 43 Controlling brush is a serious problem; roots must be killed or removed. Guineagrass recovers naturally if brush is removed. The total annual yield of forage is about 24,000 pounds per acre. 2. Hilly Clay Range Site (45 to 60 inches precipitation) This site consists of soils of the Dorothea, Isaac, Jacana, Parasol, and Victory series. These are clays and clay loams. The stratum below a depth of 20 inches does not restrict grass roots. This site is very well suited to guineagrass and pangolagrass. If it is overused, hurricanegrass be- comes abundant and brush invades. Controlling the invasion of brush, particularly of Guava brush, is a serious problem. The total annual yield of forage is about 16,000 pounds per acre. 3. Shallow Range Site (45 to 60 inches precipitation) This site occurs mostly in steep mountainous areas. It consists of soils of the Descalabrado series. These are clay loams that are less than 20 inches deep over bedrock. Guineagrass and pangolagrass make up the climax vegetation. If overgrazed, they are replaced by hurricanegrass and Barbados sourgrass. Mexican bluegrass (Chloris inflata} and brush invade as range condition becomes poorer. Controlling brush is a serious problem. Guinea- grass recovers naturally if brush is removed. The erosion hazard is severe in limestone areas denuded of vegetation. The total annual yield of forage is about 12,000 pounds per acre. 4. Deep Range Site (35 to 45 inches precipitation) This site occurs along streams, on alluvial fans, and at the base of the volcanic and limestone hills. It consists of soils of the Aguirre, Coamo, Corn- hill, Fraternidad, Fredensborg, Glynn, Lavallee, and San Anton series. These are clays and clay loams. Most are deeper than 20 inches. Guineagrass and pangolagrass make up the climax vegetation. If overgrazed, they are replaced by hurricanegrass, Mexican bluegrass, and Barbados sourgrass. Brush invades as range condition becomes poorer. Controlling brush is a serious problem. Removal of all roots by mechanical means or by the use of herbicides and good grass management keep invasion at a minimum. Guineagrass recovers naturally if brush is removed. The total annual yield of forage is about 16,000 pounds per acre. 44 dos sourgrass. 5. Hilly Clay Range Site (35 to 45 inches precipitation) This site consists of soils of the Dorothea, Isaac, Jacana, Parasol, and Pozo Blanco series. These are clay loams. The stratum below a depth of 20 inches does not restrict grass roots. This site is well suited to guineagrass but is only fairly well suited to pangolagrass. If these grasses are overgrazed, hurricanegrass and Barbados sourgrass become abundant. Brush and poor grass species, such as Mexican bluegrass, invade after continuous overuse of this site. Erratic rainfall and brush invasion are the two most critical limitations. The total annual yield of forage is about 12,000 pounds per acre. 6. Shallow Range Site (35 to 45 inches precipitation) This site occurs in mountainous areas and on foot slopes. It consists of soils of the Aguilita, Cra- mer, Descalabrado, Hesselberg, Sion, and Southgate series. The climax vegetation is guineagrass. Pangola- grass grows only on the well-managed, deeper parts of the site. Hurricanegrass and Mexican bluegrass are the principal increasers if the site is heavily grazed. Acacia, moran, and numerous other undesira- ble species also become abundant. Brush invasion is the most serious limitation. The total annual yield of forage is about 8,000 pounds per acre. 7. Deep Range Site (25 to 35 inches precipitation) This site occurs along streams, on alluvial fans, and at the base of the volcanic hills. It consists of soils of the Coamo, Cornhill, Glynn, and San An- ton series. These are clay loams that are more than 20 inches deep. The climax vegetation is guineagrass. If over- grazed, it is replaced by hurricanegrass and Barba- Brush and cactus invade as range condition becomes poorer. Erratic rainfall and brush invasion are the two major limitations. Guineagrass recovers naturally if brush is removed. The total annual yield of forage is about 12,000 pounds per acre. 8. Hilly Clay Range Site (25 to 35 inches precipitation) This site consists of soils of the Isaac, Jacana, and Pozo Blanco series. These are clay loams. The stratum below a depth of 20 inches does not restrict grass roots. The climax vegetation is guineagrass. If over- grazed, it is replaced by hurricanegrass and Barba- dos sourgrass. Continuous overuse of the site re- sults in complete invasion of brush and Mexican bluegrass. Erratic rainfall and brush invasion are the two most critical limitations. Guineagrass recovers naturally if brush is removed. The total annual yield: of forage is about 9,600 pounds per acre. 9. Shallow Range Site (25 to 35-inches precipitation) This site. occurs.in mountainous areas and on foot slopes. It consists of soils of the Aguilita, Cra- mer, Descalabrado, and Southgate series. These soils are clay loams. Guineagrass is the climax vegetation. If over- grazed, it is replaced by hurricanegrass and Barba- dos sourgrass. Continuous overgrazing results in invasion of Mexican bluegrass and numerous species of brush. Erratic rainfall and brush invasion are the two most critical limitations. Brush should be removed by mechanical means or by burning. Guineagrass re- covers naturally if brush is removed. The total annual yield of forage is about 6,000 pounds per acre. USE OF THE SOILS Approximately 34,000 acres on the Virgin Islands is woodland. Of this acreage, 20,000 acres has po- tential for timber production. About 15,000 acres of this potential timberland is in mountainous areas in the northwestern part of St. Croix and on hills in the central and southwestern parts. It is esti- mated that there ‘is 500,000 board feet of natural mahogany of commercial quality on the islands, most of which is standing on a 300-acre tract in the cen- tral part of St. Croix. A large part of the acre- age used for timber production, in fact, about 13,500 acres, is under private, generally absentee, ownership. The principal species on the islands are West Indies mahogany, which grows on all but the steepest slopes, and thibet, or woman's tongue, which is a common pasture shade tree. - Teak has been introduced recently. The desirability of these high-grade woods makes salvage of the logs practical despite the small volume involved. Nearly all wood products are utilized on the islands as craftwood, cabinet wood, fence posts, and marine items. Woodland Suitability Groups Management of woodland can be planned more effec- tively if soils are grouped according to those char- acteristics that affect growth of trees and manage- ment of the stands. The soils of the Virgin Islands have been assigned to four woodland suitability groups. Each group consists of soils that are about Spy Robert W. Nobles, Institute of Tropical Forestry, United States Forest Service. 382-314 O- 70-4 many fragments of coral and seashells. 10. Rough Stony Land Range Site (25 to 60 inches precipitation) This site occurs in volcanic and limestone areas throughout the islands. It consists of Diamond and Southgate soils, Limestone rock land, and rock land. The soils are clay loams that are shallow over rock. Guineagrass is the potential plant cover in areas where the soil is deep enough for grass roots. Pro- duction is limited because there is little soil ma- terial and little or no available moisture. 11. Coastal Sand Range Site (25 to 60 inches precipitation) The one soil in this site, Jaucas sand, 0 to 5 percent slopes, is a deep, loose sand that contains It occurs along the seashore. It is very low in moisture- holding capacity and is very droughty. The potential native plant cover is seashore dropseed (Sporobolus virginicus) . FOR WOODLAND® the same in suitability for wood crops, potential productivity, and management requirements. The fac- tors considered in assigning each soil to a woodland group include potential productivity, species to be favored in management of existing stands and to be preferred for planting, and soil-related hazards and limitations to be considered in management. Estimates of potential ‘productivity are given in annual growth in board feet for West Indies mahog- any, in plantations under intensive management, using a 75-year rotation. | Plant competition refers to invasion by unwanted shrubs and vines when openings are made in the can- opy. Competition is slight if invaders do not pre- vent adequate regeneration and early growth and do not interfere with the development of planted seed- lings. It is moderate if the invaders delay but do not prevent the establishment of a normal, fully stocked stand. Competition is severe if invaders prevent adequate regeneration or if intensive site preparation and maintenance are needed. Mahogany occurs naturally in nearly pure stands on the is- lands. In plantations, plant competition is severe. Seedling mortality refers to the expected loss of naturally occurring or planted seedlings, as a re- sult of unfavorable soil characteristics. Mortality is slight if the expected loss is less than 25 per- cent; it is moderate if the expected loss is between 25 and 50 percent; and it is severe if the e~pected loss is more than 50 percent. Seedling mortality is not a limitation in woodland management on the is- lands; mortality is seldom more than slight. Equipment limitation refers to soil characteris- tics and topographic features that restrict or pro- hibit the use of conventional equipment for plant- ing, harvesting of wood crops, road construction, AS and control of unwanted vegetation. The limitation is slight if there is little or no restriction on the type of equipment or the time of year that the equipment can be used. The limitation is moderate if the use of equipment is restricted by one or more unfavorable characteristics, such as slope, stones or. other obstructions, seasonal wetness, instabil- ity, or risk of injury to roots of trees. The limi- tation is severe if conventional equipment cannot be used. The hazards of drought, exposure, and a high transpiration rate make most east-facing slopes on the islands unsuitable for timber production. The woodland groups on the islands are described in the following paragraphs. The soil series rep- resented are named in the description of each site, but this does not mean that all the soils of a given series are in the site. The woodland group desig- nation for each soil on the islands can be found in the "Guide to Mapping Units." Woodland Group 1. This group consists of soils of the Dorothea, Isaac, Magens, and Victory series. These soils are moderately fine textured, are well drained, and are deep over highly weathered volcanic rocks (sapro- lite). They occur on side slopes of dissected vol- canic uplands. The slope gradient is 12 to 60 per- cent. Drainage is good. Runoff is medium to rapid, permeability is moderate, and the available water capacity is high. These soils are used mostly for terraced, cultivated crops and for pasture. Annual growth is estimated at 150 to 250 board feet per acre each year. Mahogany should be selected for planting and favored in existing stands. The amount of moisture available causes moderate competition from unwanted trees, shrubs, and vines but normally insures only slight seedling mortality. The equipment limitation is slight if the slope is less than 20 percent, moderate if it is between 20 and 40 percent, and severe if it is more than 40 percent. Woodland Group 2 This group consists of soils of the Aguilita, Fredensborg, Pozo Blanco, Sion, and Diamond series, and Limestone rock land. The soils are moderately fine textured to fine textured, are well drained, and are shallow and moderately deep over soft marly limestone. They occur on alluvial fans, foot slopes, and low hills, mostly on St. Croix. The slope gradient is 0. to 60 percent. Drainage is 46 good. Runoff is medium to rapid, permeability is moderate, and the available water capacity is moderate. About 90 percent of the acreage in natural. mahog- any forest on St. Croix is on these soils. Mahogany should be favored in existing stands. Both mahogany and teak are suitable for planting (pl. II). The amount of available moisture causes severe competi- tion from unwanted trees and shrubs in natural areas and from shrubs, grasses, and weeds in plantations. Seedling mortality is:slight. The equipment. limi- tation is slight. Woodland Group 3 This group consists of soils of the Glynn, Laval- lee, Parasol, and San Anton series. These are mod- erately fine textured, well-drained soils that are deep over stratified sediments of varying textures. All are on alluvial fans and flood plains. Drainage is good. Runoff is medium, permeability is moder- ate, and the available water capacity is moderate to high. These soils are generally not used for timber production, but if they are, excellent mahogany and teak plantations can be expected. Annual growth is estimated at 250 to 350 board feet per acre each year. ‘The supply of moisture is good to poor. If rainfall is plentiful, plant competition is very severe. Generally, seedling mortality is slight. The equipment limitation is slight. Woodland Group 4 This group consists of soils of the Cramer, Isaac, Descalabrado, Jacana, and Southgate series. These are moderately fine textured, well-drained soils that are moderately deep and shallow over hard volcanic rock. They are on side slopes of dissected volcanic uplands. The slope gradient is 2 to 60 percent. Drainage is good. Runoff is medium to rapid, permeability is moderate, and the available water capacity is low to medium. Annuel growth is estimated at 150 board feet per acre on the upper slopes and 300 board feet per acre on the lower slopes. Mahogany is the preferred species for planting, but teak may be planted on the deep soils on lower slopes. The degree of slope and the availability of moisture vary greatly. Plant competition is moderate on the upper slopes and severe on the lower slopes. Seedling mortality ranges from slight to moderate. The equipment limitation is slight if the slope is less than 20 percent, moderate if it is between 20 and 40 per- cent, and severe if it is more than 40 percent. USE OF THE SOILS IN ENGINEERING Some soil properties are of special interest to engineers because they affect the construction and maintenance of roads, building foundations, water storage facilities, erosion control structures, and sewage disposal systems. Among the properties most important to engineers are permeability, shear strength, density, shrink-swell potential, water- holding capacity, grain-size distribution, plastic- ity, and reaction. Depth to the water table, depth to bedrock, and topography also are important. Information concerning these and related soil properties is furnished in tables 5, 6, and 7. The estimates and interpretations in these tables can be used in-- 1. Planning and designing farm ponds and other structures for controlling water and conserv- ing soil. 2. Selecting locations for highways, airports, pipelines, and underground cables. 3. Locating sources of sand, gravel, or rock suitable as construction material. 4. Selecting areas suitable for industrial, com- mercial, residential, and recreational devel- opment. The engineering interpretations reported here do not eliminate the need for sampling and testing at the site of specific engineering works involving heavy loads and excavations deeper than the depths of layers here reported. Even in these situations, however, the soil map is useful in planning more de- tailed field investigations and in indicating the kinds of problems that may be expected. Some of the terms used by soil scientists have special meanings in soil science that may not be fa- miliar to engineers. These terms are defined in the Glossary. Engineering Classifications The two systems most commonly used in classifying soils for engineering are the systems approved by the American Association of State Highway Officials (AASHO) and the Unified system. The AASHO system (1) is used to classify soils ac- cording to those properties that affect use in high- way construction. In this system al] soil material is classified in seven principal groups, on the ba- sis of grain-size distribution, liquid limit, and plasticity index. The groups range from A-1, which consists of soils that have the highest bearing strength and are the best soils for subgrade (founda- tion), to A-7, which consists of soils that have the lowest strength when wet. Within each group the relative engineering value of the soil material is indicated by a group index number. The numbers range from 0, for the best material, to 20, for the poorest, The group index number is shown in paren- theses following the soil group symbol. In the Unified system (7) soils are classified ac- cording to their téxture and plasticity and their performance as engineering construction material. Soils are grouped in 15 classes. There are eight classes of coarse-grained soils, identified as GW, GP, GM, GC, SW, SP, SM, and SC; six classes of fine- grained soils, identified as’ML, CL,-OL, MH, CH, and OH; and one class of highly organic soils, identified as Pt. Soils on the borderline between two classes are designated by symbols for both classes; for ex- ample, MH-CH. The textural classification system used by the U.S. Department of Agriculture is primarily for ag- ricultural use but is also important in engineering. In this system the texture of the soil depends on the proportional amount of the different sized min- eral particles. The sizes are designated as cobble- stones, gravel, sand, silt, and’clay. The textural classes range from the fine-textured clays, silty clays, and sandy clays to the coarse-textured loamy fine sands, loamy sands, sands, and coarse sands. Table 7 shows the AASHO and Unified classifica- tions of specified soils on the islands, as deter- mined by laboratory tests. Table 5 shows the esti- mated classification of all the soils in the survey area according to all three systems of classifica- tion. Estimated Properties of the Soils Estimates of soil properties that are significant in engineering are given in table 5. The estimates are based on data shown in table 7, on tests of sim- ilar soils in the survey area, and on past experi- ence in engineering construction. Permeability indicates the rate at which water moves downward through undisturbed and uncompacted soil material. The rate depends largely on the tex- ture, structure, and porosity of the soil. Plow- pans, surface crusts, and other properties resulting from the use of the soils are not considered. Available water capacity is the amount of capil- lary water in the soil and available to plants, after all free water has been drained away. Reaction, the degree of acidity or alkalinity, is expressed aS pH value. The pH value and relative terms used to describe soil reaction are explained in the Glossary. The shrink-swell potential indicates the volume change to be expected with a change in moisture con- tent. The estimates are based primarily on the amount and type of clay in the soil. The shrinking and swelling of soils damages building foundations, roads, and other structures. A high shrink-swell potential indicates hazards to the maintenance of structures constructed in, on, or with such mate- rial. Interpretations of Engineering Properties Estimates of the suitability of the soils for various engineering uses are given in table 6. Fea- tures or characteristics that are likely to affect 47 Soil and map symbol Aguilita: AgB, AgC2, 4-14 AgD, AgE, AgF. Aguirre: AuA----------- 60+ Coamo; CaB------------- 60+ Cobbly alluvial land: 60+ Cb s Cornhill: CoA---------- 60+ Cramer: CrC, CrE, CrF, 10-20 CsE2, CsF, CvE. Descalabrado: DeD, DeE,/ 10-20 DeF. Diamond: D1B, D1C2----- 8-16 For Limestone rock land part, see Lime- stone rock land. Dorothea: DoE, DoF-----| 24-37 Fraternidad: FcA, 60+ FceC2. Fredensborg: FrA, FrB, 10-20 Frc2. Glynn: GyB, GyC2------- 60+ Hesselberg: HeA-------- 10-20 Isaac: IsD2, IsE, IvD--| 20-72 See footnotes at end of table. 48 10+ 10+ 10+ 10+ 10+ 10+ 10+ 10+ 10+ 10+ TABLE 5.--ESTIMATED {Volcanic rock. Classification USDA texture Unified Gravelly clay loam------------------------ GC Soft limestone---------------------------- CL Clay-------+----------~-------~------------ CH Clay loam----------------------~----~---.~-- CH or MH Clay------------------------------~----~-- CH Clay loam----------------~---------+------- CH or MH Gravelly clay loam, clay loam, and gravel. '|Gravelly clay loam------------------------ CL or ML Clay loam---------------+-----------~-+---|]CH Clay------------+--------~----------------- CH Gravelly clay----------------------------- CL or ML Gravelly clay loam------------------------ GM or ML Clay and gravelly clay---~---------------- CL Volcanic mudstone. Clay loam--------------------------------- MH or CH Silty clay loam---~------------------------ ML or CL Volcanic rock. Clay loam--------------------------------- ML or CL Loam- ------------------------------------- ML or CL Limestone, Clay loam--------------------------------- MH or CH Clay-----------------------------+-~-------- MH or CH Clay loam--------------------------------- MH or CH Clay---------~----------------------------- CH Clay-------~------------------------------ CH Clay-------------+-------------------------- CH Clay, silty clay loam------------------ ---1MH or CH Silt loam, soft marl, and limestone-~------- CL Clay loam--------------------------------- Clay, clay loam : : : Clay loam, sandy loam, and clay Clay-------------------------------------- MH Clay~-------------+-------~------------------ MH Limestone-------------------+-------------- GM Limestone. Gravelly clay loam------------------------ GM or ML Clay---------------- 4-22-2222 -----------e CL Clay loam------------------~-------------- cL AASHO PROPERTIES OF THE SOILS 55-65 99 100 80-90 85-95 80-90 | ___s Percentage passing sieve-- | | ___s Percentage passing sieve-- | sieve-- 45-55 82 90-100 70-80 75-85 70-80 65-75 90-100 90-100 70-80 55-65 65-75 80-90 90-95 90-100 85-95 90-100 90-100 90-100 80-90 90-100 90-100 85-95 80-90 80-90 95-100 90-100 85-95 90-100 25-35 §5-65 65-75 658-75 30-40 56 75-98 65-75 70-80 65-75 70-80 70-80 75-95 75-85 45-55 55-65 70-80 65-75 70-80 60-75 65-75 70-80 65-75 78-85 85-95 80-90 75-85 56-70 65-75 85-95 80-90 80-90 90-100 15-25 45-55 55-65 55-65 Permeability In. /hr. ooo nN o a °o oooedg NO T °o yo er) n w ' nN ooo N c Oo Available water Reaction capacity 0.15-0.20 6.6-7.3 0.15-0.20 7.4-8.4 0.15-0.20 7.4-8.4 0.15-0.20 7.4-8.4 0.15-0.20 7.4-8.4 0.15-0.20 7.4-8.4 0.15-0.20 7.4-8.4 0.15-0.20 6.1-7.3 0.15-0.20 1-7.3 0.15-0.20 6.1-7.3 0.10-0.15 6.1-7.3 0.15-0.20 6.6-7.3 0.10-0.15 7.4-8.4 0.15-0.20 5.6-6.5 0.15-0,.20 5.6-6.5 0.15-0.20 5.6-6.5 0.15-0.20 7.4-8.4 0.15-0.20 7.4-8.4 0.15-0.20 7.4-8.4 0.15-0.20 7.4-8.4 0.10-0.15 7.9-8.4 0.10-0.15 6.6-7.8 0.10-0.15 6.6-7.8 0.15-0.20 6.1-7.3 0.15-0.20 6.1-7.3 0.15-0.20 6.1-7.3 Shrink-swell potential Moderate. Moderate. Very high. Moderate. Moderate. Moderate. Moderate. Moderate. Very high. Moderate. Moderate. Moderate. Moderate. Moderate. Low. Low. Moderate. Moderate. Moderate. High. Very high. Very high. High. Moderate. Moderate. High. High. High. High. Moderate. Moderate. Moderate. 49 Soil and map symbol Jacana: JaB, JaC, JaD-- Jaucas: Jub? se ab fae Lavallee: LaB---------~- Leyeled clayey land: Le’. Leyeled marly land: Ln’, Leyeled rocky land: Lr Ligestone rock land: Ls”. Made land: Mal? a Magens: MgF-----~------ Parasol: PaB, PaC------ Pozo Blanco: PbC, PbD-- Rock land. No estimates. San Anton: SaA, sacl_-- Sion: ScB, ScC--------- Southgate: SgE, SgF, SrF. Tidal flats: T£??.---- Tidal swamp: Ts’ ’"----- See footnotes at end of table. 50 Depth to-- 10+ 10+ 10+ 10+ 10+ S+ 10+ 10+ 10+ 5+ 10+ TABLE S.--ESTIMATED PROPERTIES Classification SDA texture Unified Gravelly clay----------------------------- Volcanic rock. Gravelly clay loam--------------~---------- Very gravelly loam------------------------ Volcanic rock. OF THE SOILS--CONTINUED Percentage passing sieve-- Available : Permeability water Reaction No. 4 No. 10 No. 200 capacity In. /hr. pH 85-95 85-90 80-90. 70-80 0.20-0.63. 6.1-7.3 85-95 85-90 80-90 70-80 0.20-0.63 6.1-7.3 100 100 90-95 65-75 0.63-2.00 6.1-7.3 100 100 85-95 5-15 6.30-20.0 0.05-0.10 7.4-8.4 75-85 70-80 65-75 70-80 0.20-0.63 0.15-0.20 6.1-7.3 55-65 45-55 45-55 30-40 0.63-2.00 0.10-0.15 6.6-7.8 100 100 95-100 85-95 0.63-2.00 0.10-0.15 5.1-6.0 100 100 90-100 75-95 0.63-2.00 0.15-0.20 4.5-5.5 100 100 90-100 70-80 0.63-2.00 0.10-0.15 4.5-5.5 90-100 90-100 80-90 60-70 0.63-2.00 0.10-0.15 5.1-5.5 100 100 80-90 58-70 0.20-0.63 0,.15-0.20 6.6-7.3 100 100 70-80 51-60 0.63-2.00 0,10-0.15 6.6-7.8 100 100 90-100 70-80 0.63-2.00 0.10-0.15 6.6-7.8 100 100 95-100 85-95 0.63-2.00 0.15-0.20 7,4-8.4 100 100 85-95 60-75 0.63-2.00 0.10-0.15 7.4-8.4 85-95 85-95 80-90 70-80 0.63-2.00 0.15-0.20 6.1-7.3 75-85 70-90 65-75 70-80 0.63-2.00 0.10-0.15 6.6-8.4 100 100 90-100 70-80 0.63-2.00 0.15-0.20 7.4-8.4 99 90-100 85-95 75-85 0.20-0.63 0.15-0.20 7.4-8.4 99 97 75-85 56-65 0.63-2.00 0.10-0.15 7.9-8.4 85-95 8S-95 80-90 70-80 0.63-2.00 0.15-0.20 §.1-6.0 55-65 45-55 | 45-55 30-40 2.00-6.30 0.10-0.15 $.6-6.5 Shrink-swell potential High. Moderate. Moderate. Very low. Moderate. Low. Low. Low. Low. Maderate. High. Moderate. Moderate. Moderate. Moderate. Moderate. Low. Moderate. Moderate. Moderate. Moderate. Low. 51 TABLE 5.--ESTIMATED PROPERTIES a Victory: VcD, VcE------} 60+; 10+ | O-22)Clay loam---------------~----------------- MH or CH/A-7 Vojcanic rock land: Vr". loupject to flooding. Classification Seasonal high Soil and map symbol USDA texture 52 OF THE SOILS--CONTINUED | ___s=Percentage passing sieve-- | passing sieve-- Permeability No. 10 No. 200 In. /hr. 100 -| 90-100 65-75 0.63-2.00 Material variable. Onsite determination is necessary. 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-oeduos poos *AQVITI GUIs ITey *yQ8uerys Teays MOT SpeutF -uod ssertun AYITTGeIsS 100g SBUIPTING MOT IOF suotTzepunog ‘atqeo tidde ou aoTqIeVIg “AVITTG Tssorduos uMT pew Suotzoed -WOd ITez SA3TT Tq -e3S ITey “ARTTIG -Tssoid -wod ysTy fuotqoed -wo2d 1ood SAQTITG -B35 100g “AUTITG tssoiduos unTpeu 03 3Y48TTS Suotzoed -wod poo3 *AIYTTTG -B3S ITey AzTTTqeou ‘rod ptdex ‘8utdrd ‘ITT TG -84S 100q *atqeottdde you 92T 981g ‘eT qeloaes sainieey LIV * aT qeroAes seinjees TLV ‘a8e -daas SsroAeT ATTAaery *TeTlszew ‘aoeyains Ieeu LO 78 Yyoorpeg “aT qeloaey sainjeey TIV ‘ABTS 9T2 -setd ‘etqeisug ‘aT qeroaes seinjeesy LIV “opty ygty B8utinp 3ur snotaied Ara, |-pooTy 03 39efqGns --3utq.ejje sainjeaz [Ios uotzesoT ASMUZTH spuod wie4 --jO sd1n0s se *yoorpaq *yoorpeq pesodxe : 100g Ipasodxe : 100g *AYTAtT ONpoad soeeuds ~--1Tey MOT :100qg * keto *k¥TO otysetd :200g prysetd : 100g sets eciateesets poo ;} TeAer3s sites *Aqtoed -e89 9in stow PIQeTT@Ae MOT *pautz f Ay TAT ONpord -uod JT poo MOT + 100d IITZ peoy Ttosdoy ATT TQeIINS "LT i puel AYDOL paTeadeyT ‘Wy: pUuey A[LOWU PSTSAST ‘OT :puet AvkelD palsaoy ---ge] :99T [PART I-----gne :seoner stoquds dew pue {ToS 57 * MOT e *MOTAQ poos| -2q poo3 fol ATeZ Ssayout 01 ates 81 zsowzeddn |fseyout gt Poul ut ATTTqeis| isomroddn jzood pue AITT Tq] ut AIITTG pop |-tsserduos ystH| -e3s 100g “AVIITG -Tssoid -wod ysTty 01 uMTpow gow |*AYT[Tqeis 100d SAVIITG pou }oy xrtez {AZI[TTqG] -eys 100d pow |-Tsseaduwos ysty 0} Ite “AVITTG -tssoid -wod YysTty fuotqzoed -wod rood ‘AVITTQtssead 02 ITez -wod ysty fuotz fAVTITG OTS -oedwod atez] -eas rood AOS }{AVTLTqe1s Ite 0} ITeW *sutdtd “AVTITG] ADIT Tqeow -eouzed ptdez|-zed ptdes ‘surdtd 02 fuotyoed 20efqns fuot i] -wod itey -seduos 1tez fAVTITG TIS] {AITL[Tqeys TOog) -eIs 100g ey 10 *atTqes 03s ‘goejains reoul]-trdde you AVS] IO 2e aUuoZSOUTT adT{eIg sSuTPTIng MOT OZ SUOTEpuUNOY “Tet? -uaqod a8ei01s soonpet ado[s {siakeT sutck{azepun SNOTAIOg *SIOABT sutrA[zepun ut a3edaes “Tet. -uazod a8ei0is saonper sedots *[eT19} eu snotazed Arle, ‘otqeottdde Jou 90T}0eIg “STTTJ pue syno oJ peau fsyueq -peor uo pesod “XO FF OT qtposg *[ Tosqns atqeysun ‘3TIse1d "3272 BABIXS pue [ney 03 Asta SSI[TJZ pue szno IOZ paosu fsyueq -peoz uo pesod -x9 JT ST qtporg ‘opt? ysTy sutanp pepoots aq ABW "90RJans Ieou LO 38 QU01SeUTT ‘AY ‘Tet uaz0d -[TQIssaoae TLeMs-yUTIYys | uo Butpuedep aqeropow :1tey |‘itezy 02 pooyg *[Tosqns Aeqzo oryseqd :ateg |--------- pooy ‘aedots Fo ‘ado[s Jo asneo| asnedeq uted -aq AYITTQtTSsseD| -qo 02 3[N> -9e rood :atey| -TJJIp :1tegd ‘eT qelTteae [etio.ew Jeceee eels pooyj|TTos ou :100q * QUOTSOWTT * QUOISOUTT pesodxs :100g |pesodxa :100g Bole ITOALOSOY spuod wiry ~-SuT}.eFje sainjzeosy [tog uotzes0{ Aemusty TITF peoy Ttosdoy --JO 90an0s se AYTIIGezINS penu FHL AO SAILYYdOWd ONIUAANIONA AO NOILVLAUdYSLNI--°9 FTAVL “d9d ‘949d :oDuRTg OZ0g “Oed ‘qeq :[oseieg cern A8W i suedey ---tW ipuel open "Ss :pueyt yoo. 9uo SOUT stoquds dew pue [Tos 58 i eM 9S eM 95 [ Ss * pepoolF Ajtrensn fatqez zo}zeM YSTH ‘atqe. 1938 Y3tH *yv0rpeq I9AO MOTTeUS *szokeT BSUTAT -iopun UT ITeZ faaABl aes -ains ut AdITTq -e3s Iood pue uotzoeduos 100g ‘uot oedwos zood $A3TTTq -tssarduod ystH SSUTPTING MOT TOF suoTIepuno, ‘aTQeTIeA fT eTreqeuw OTUBSIO ~-eTqeTIEA ‘90ano0s je [eTieleEW JO sUMT[OA perTwtt S901 IaA0 MOTTeUS ‘MOT -9q poo3 02 Ite Srakel ooezins uT uoTzoed -wod 100g suotqzoed -woo rood *AYTTTG -B1S 100g quewyue quy “anoaee pa.epunul “eT qe? 193e4 YSTH *yeTy -uezod a3ei101s seonpez adots feBedses !yo0r peanzcoeig “aT QeLoaRs soinqzeos lV ‘ase -deas fsi1okeT ATT@AbID Bele ITOATASOY spuod wiej --pepooTs ATTensy *SUTpooTZ yuonb -91F 02 yeLfqns feTqe} reqzem ysty “STILTS pue syn. 10F poou fsyueqpeor uo pesodxo FT SLqTporls Ssayout 0Z 03 OF FO Yadep *ZaAeT aoeszans 31} -setd ATA eLAapo,| *sedorts dadee3s uo ST{TF pue sind 10} peeNn uote 0, Aemys TH --Butjoezye seinjeay [ToS B 1B yOorpeg. ‘pa -pooT}s AT[Tensn fpeuteip AjTaiood :100g “oT qed I9}@M LOAO MOTLBYS :100g *yoo0L IeA0 MOTTBYS :100g *TetTquei0d TTems-yUTIYS a }ePISpou :ITey *[eTQuez0d []omS-yuTIYsS a,eIepou :ATey TITF peou °sqles DTXO} :100g |-S] :duwems [epry “*s778s "FL 9TxX0} :100g :S2elTF Lepr ‘AUT -[Tqtsseo08 uo 3utpusdop ‘zood 0} iI1eq ‘ats ‘48s *q8S :eqesyiNnoSs * QUO SOUTT JOS IOAO OTTBYS :1Teq j--99S ‘GIS :uoTS “Des Heseeese pooy ‘yes :uojUuy ues *suoTqe2 -o91di9 UT ON “puel YON [tosdo], stoqucxs dew pue [10S --jJO 9dIn0s se ATT IqeyINs 59 "yor DTUBSTOA pesodxe :100g|/pesodxe :100g *eTqeo -ttdde jou aot ORI ‘IA i puet YOL ITUBITOA ‘atqeottdde zou adT ORIG ‘eoesans re9u Io 3e@ yooLpeg a ag *aoezans reeu Jo 3@ yI0I prey ‘kt Ttqtsseid -wod ysty oj] ‘uot zoed * squouDjue q ‘edorts ‘AQT untpew {AAT[tq| -woo 100d *[BT4] -we uo pesodxe FT JO osnedeq| -[TqTsseooR “POA §qoa :AIOVOTA AVITTQISse0| uo Sutpuedep -ov zood :ateg|‘atood 02 aTeq aTQrpote !STITZ pue s3znd Loz pooy -usqod a3e101s seonpez edo[s -B3S rood fuotz -vedwos 100g SAQTITG -BYS LOOg yUsUYyURqUY | Fale ITOATESeY spuod wiej SBUTPT Enq MOT aioF suoTIepuNno; stoquAs deu pue [Tos uotzeB.07 AemysTH TLtF peoy Trosdoy --JO 902n0s se AIT[Tqeatns --BuT19esje Ssain3zeez [ToS pen zuoo--STI dHL dO SHILYddOUd ONIMAANIONA AO NOLLVLAUdYaLNI--"9 ATEVL 60 various engineering practices were considered, and evaluations were based on test data and field per- formance. The estimates apply to the depth indica- ted in table 5. ; Topsoil is a term used to designate a fertile soil or soil material, ordinarily rich in organic matter, that is used as a topdressing for lawns, gardens, and roadbanks. The information in table 6 indicates suitability for such use. Road fill is material used to build embankments. The estimates in table 6 indicate the suitability of soil material moved from borrow areas for this pur- pose. -Among the features considered for highway loca- tion are the flood hazard and the depth, stability, and erodibility of the soil material. Farm pond reservoir areas are affected mainly by slope (pl. II) and loss of water through seepage. The soil features mentioned in table 6 are those that influence seepage and potential storage capacity. Farm pond embankments serve as dams, The soil features considered in constructing pond embankments include depth, permeability, stability, compaction characteristics, and shrink-swell potential. Foundations for low buildings are affected chief- ly by features of the undisturbed soil that influ- ence its capacity to support the normal foundation loads. Among the features considered are stability, shrink-swell potential, compaction characteristics, depth, and susceptibility to flooding. Specific values of bearing strength are not given in the table, and none should be inferred. Septic tank filter fields are affected mainly by permeability, depth to the water table, slope, depth to bedrock, and susceptibility to flooding. Both the degree and the kind of limitation are given in table 6. Sewage lagoons are influenced chiefly by such features as permeability, slope, depth to bedrock, and number of coarse fragments. The degree and the kind of limitation are: given. Cramer gravelly clay loam, Descalabrado clay loam, and Southgate clay loam make up a large per- centage of the total acreage of the Virgin Islands. These soils are steep and are shallow over bedrock. They have severe limitations for most engineering uses. Aguilita gravelly clay loam, Fredensborg clay, and Sion clay loam are shallow and moderately deep over soft limestone. Limitations resulting from the slope and the plastic surface layer are readily overcome by land forming. 382-314 O- 70-5 Aguirre and Fraternidad clays have slow permea- bility and a very high shrink-swell potential. The limitations are severe for most engineering uses. Diamond clay loam and Hesselberg clay are shallow over hard limestone. They have severe limitations for most engineering uses. Dorothea clay loam, Victory clay loam, and Magens silty clay loam are steep, but they are deep over very highly altered volcanic rocks. Limitations resulting from slope are readily overcome by land forming. Jaucas sand is the only soil suitable as a source of sand for structural purposes. There are some gravelly soils, but the gravel is not clean and is not suitable for construction purposes. Engineering Test Data tor Soils Soil samples taken from eight: profiles on the island of St. Croix were tested in accordance with standard procedures to help evaluate the soils for engineering purposes. The tests were performed by the Bureau of Public Roads. Table 7 shows the re- sults of tests to determine particle-size distribu- tion and other properties significant in soil en- gineering. Mechanical analysis shows the percentages, by weight, of soil particles that pass sieves of speci- fied sizes. Sand.and other coarser materials do not pass through the No. 200 sieve. Silt is the mate- rial larger than 0.002 millimeter in diameter that passes through the No. 200 sieve, and clay is the material smaller than 0.002 millimeter in diameter that passes the No. 200 sieve. The clay fraction was determined by the hydrometer method. Liquid limit and plasticity index indicate the effect of water on the strength and consistence of soil material. As the moisture content of a clayey soil is increased from a dry state, the material changes from a solid to a plastic state. If the moisture content is further increased, the material changes from a plastic to a liquid state. The plas- tic limit is the moisture content at which the soil material passes from solid to plastic. The liquid limit is the moisture content at which the material changes from plastic to liquid. The plasticity in- dex is the numerical difference between the liquid limit and the plastic limit. It indicates the range of moisture content within which a soil material is plastic. The AASHO and Unified classifications are ex- plained under the heading "Engineering Classifica- tions." 61 [Tests made by Bureau of Public Roads (BPR) in accordance with standard Soil name and location Cramer gravelly clay loam: 1.8 miles NW. of-Annaly and 100 feet to the right of Scenic Drive. (Ortho) 0.15 mile S. of Centerline Rd. and 50 feet E. of main entrance to Cotton Valley. (Thick B2t horizon) Descalabrado clay loam: 1.75 miles W. of Fountain-LaVallee and 50 feet NE. of Scenic Drive. (Ortho) Fraternidad clay: 0.3 mile W. along N. side of Lower Love and 400 feet N. of farm road. (Ortho) Fredensborg clay: 0.25 mile W. of Kingshill Police Station and 150 feet W. and 75 feet N. of road intersection. (Ortho) Glynn clay loam: 300 feet S. of church in SW. corner of Grove Place and 60 feet W. and 30 feet N. of light pole. (Ortho) Hesselberg clay: 0.7 mile W. of S. entrance to airport and 470 feet S. on secondary road and $0 feet W. of road. (Ortho) Parasol clay loam: 1.3 miles N. of oil road and 100 feet S. and 75 feet W. of gate on road to River. (Ortho) Parent material Volcanic rocks (Caledonia forma- tion). Sediments derived from basic volcanic rocks and local residuum, Basic volcanic rocks. Sediments derived from residuum of volcanic and lime- stone rocks. Alluvium derived from limestone. Alluvium derived from volcanic rocks. Residuum from limestone. Sediments derived from intrusive ig- neous rocks (Gab- bro). TABLE 7,--ENGINEERING Mechanical analysis! Percentage passing sieve-- l sccording to AASHO Designation: T 88-57, "Mechanical Analysis of Soils," in "Standard Specifications for Highway Materials and Methods of Sampling and Testing," pt. 2, Ed. 8 (1961), published by AASHO. Results by this procedure may differ somewhat from results obtained ty the soil survey procedure of the Soil Conservation Service (SCS). In the AASHO procedure, the fine material is analyzed by the hydrometer method, and the vari- ous grain-size fractions are calculated on the basis of all the material, including that coarser than 2 milli- meters in diameter, In the SCS soil survey procedure, the fine material is analyzed by the pipette method, 62 TEST DATA FOR SOILS procedures of the American Association of State Highway Officials (AASHO) ] Mechanical analysis!--con. Classification Percentage passing sieve--con. Percentage smaller than-- Plastic- ity Unified? No. 40 No. 200 0.042 mm, 0.074 mm.) | 0.05 mm.| 0.02 mm.| 0.005 mm. | 0.002 mm. SM or SC MH or CH ML or CL MH or CH ML or CL MH or CH ML or CL and the material coarser than 2 millimeters in diameter is excluded from calculations of grain-size fractions. The mechanical analysis data used in this table are not suitable for naming textural classes for soils. 2505 and BPR have agreed to consider that all soils having plasticity indexes within 2 points from A-line are to be given a borderline classification. Examples of borderline classifications obtained by this use are SM or SC, MH or CH, and ML or CL. 63 USE OF THE SOILS FOR RECREATIONAL DEVELOPMENT The information in the following paragraphs and in table 8 can be used as a guide in determining the suitability of sites on the Virgin Islands for rec- reational development. The degree and kind of limitation of the soils for specified recreational uses are given in table 8. The degrees of limitation are expressed as slight, moderate, and severe. Golf fairways.--Soils used as golf fairways should be suitable for foot traffic and vehicular traffic. Soils that have only a slight limitation are nearly level, productive, and free of coarse fragments. The suitability of the soils for the rough or for hazards was not considered’ because of the extremely wide variety of soils that are suitable for these parts of the golf course. Not considered also was the suitability of the soils for greens, because most greens are man made. Campsites.--The areas used frequently as camp- sites, including tent and trailer sites, should re- quire little preparation. They should be suitable for unsurfaced parking lots for cars and camp trailers and for heavy traffic. The most suitable sites are nearly level to gently sloping, have a firm surface, are free of coarse fragments and rock outcrops, are permeable and have good drainage, and are not subject to flooding. .The suitability of the soil for supporting vegetation should also be considered in selecting a campsite. 64 Picnic areas,--The limitations of the soils for use as picnic areas are based on soil characteris- tics. Other factors, such as the number of trees or lakes in the area, that. affect the desirability of the site were not considered. The most suitable sites are nearly level to gently sloping, have a firm surface, and have good drainage. They should ‘be free. of stones and rocks and.should not be sub- ject to flooding. The suitability of the soils for supporting vegetation should also be considered. Intensive play areas.--Areas used for playgrounds and for organized games, including baseball, foot- ball, and badminton, are subject to heavy foot traf- fic. The soils selected should be nearly level, have a firm surface, and have good drainage.. The most desirable soils are also free of coarse frag- ments and rock outcrops. It is assumed that a good vegetative cover can be established and maintained where needed. Paths and trails.--The limitations of the soils for use as bridle paths and trails for hiking, and for other nonintensive uses that involve random movement of people are based on the slope, the soil texture, the degree of wetness, and the hazard of flooding. Other factors that affect the desirabil- ity of a site were not considered. Some soils that have severe limitations. and would require consider- able preparation and maintenance would nevertheless be desirable because they are in a scenic location. Aguil Aguir Coamo land: Cornh TABLE 8.--DEGREE AND KIND OF LIMITATION.FOR SPECIFIED RECREATIONAL USE Intensive play Golf fairways Campsites Picnic areas areas Soil ita: re: AuA------- : CaB--------- Cobbly alluvial Cb. 111: CoA------ hae Doseteelsoeass Severe: Severe: coarse fragments. Severe: coarse fragments. Severe: coarse fragments ; slope. Severe: coarse _ fragments; slope. Severe: coarse fragments; slope. Severe: poor trafficability. Severe: coarse fragments. Severe: coarse fragments. coarse fragments. Severe: coarse fragments ; slope. Severe: coarse fragments; slope. Severe: coarse | fragments ; slope. Severe: coarse fragments ; slope. . Severe: coarse fragments; slope. Moderate: coarse] Moderate: soil fragments. Moderate: slope; coarse frag- ments. Moderate: fragments; slope. Severe: slope--- Severe: slope--- Severe: wetness; flooding.. Moderate: soil texture. Severe: flood- ing. Moderate: coarse fragments. Severe: coarse fragments. Severe: coarse fragments ; slope. Severe: coarse fragments ; slope. Severe: stoni- ness; slope. Severe: stoni- ness; slope. Severe: coarse fragments: slope. coarse texture. Moderate: slope; soil texture. Moderate: slope; soil texture. Severe: slope---- Severe: slope---- Severe: wetness; soil texture. Moderate: soil texture. Severe: flood- ing. Moderate: soil texture. Moderate: slope; soil texture. Severe: slope---- Severe: slope---- Severe: slope---- Severe: slope---- Severe: slope---- Severe: coarse fragments ; Slope. Severe: coarse fragments ; slope. Severe: coarse fragments ; slope. Severe: coarse fragments; slope. Severe: coarse fragments ; slope. Severe: wetness; soil texture. Moderate: | Slope. Severe: flood- ing. Severe: coarse fragments. Severe: coarse fragments; slope. Severe: coarse ‘fragments; slope. Severe: coarse fragments; slope. Severe: stoni- ness; slope. Severe: stoni- ness ;- slope. Severe: coarse fragments ; slope. Paths and trails Moderate: soil texture. Moderate: soil texture. Moderate: slope; soil texture..- Moderate: slope; soil texture. Severe: slope. Severe: wetness; soil texture. Moderate:: soil texture. Severe: stoni- ness. Moderate: soil texture. Moderate: soil texture. Moderate: slope; soil texture. Severe: slope. Severe: stoni- ness. Severe: stoni- ness; slope. Moderate:- soil texture. 65 TABLE 8.--DEGREE AND KIND OF LIMITATION FOR SPECIFIED RECREATIONAL USE--CONTINUED Soil Descalabrado: Fraternidad: FeC2. Fredensborg: Hesselberg: HeA---- 66 Severe: slope---- Severe: slope---- Severe: slope---- Severe: coarse fragments. Severe: coarse fragments. Severe: slope---- Severe: slope---- Severe: poor trafficability. Moderate: fair trafficability. Moderate: fair trafficability; slope. Moderate: slope-- Moderate: fair trafficability. Severe: slope---- Severe: slope---- Severe: coarse fragments. Slight----------- Moderate: slope; soil texture. Severe: slope--- Severe: slope--- Severe: rocki- ness. Severe: rocki- ness. Severe: slope--- Severe: slope--- Severe: soil texture, Severe: soil texture. Severe: soil texture. Moderate: soil texture. Moderate: slope; soil texture. Severe: soil texture, Moderate: slope; soil texture. Severe: slope--- Moderate: slope; coarse frag- ments. Moderate: soil texture. Moderate: slope; soil texture. Moderate: slope; soil texture. Moderate: slope; soil texture. Severe: slope---- Severe: slope---- Severe: rocki- ness. Severe: rocki- ness, Severe: slope---- Severe: slope---- Severe: soil texture. Severe: soil texture. Severe: soil texture. Moderate: soil texture. Moderate: slope; soil texture. Severe: ‘soil texture, Moderate: slope; soil texture. Severe: slope---- Moderate: slope; soil texture. Moderate: soil texture. Moderate: slope; soil texture. Moderate: slope; soil texture. Intensive play Golf fairways Campsites Picnic areas areas Severe: slope--- Severe: slope--- Severe: slope--- Severe: rocki- ness. Severe: rocki- ness; slope. Severe: slope--- Severe: slope--- Severe: soil texture. Severe: soil texture. Severe: soil texture. Moderate: slope; soil texture. Severe: slope--- Severe: soil texture. Severe: slope--- Severe: slopé--- Severe: slope--- Moderate: slope; soil texture: Severe: slope--- Severe: slope--- Paths and trails Moderate: soil texture. Moderate: soil texture. Severe: slope. Severe: rocki- ness. Severe: rocki- ness. Moderate: slope; soil texture. Severe: slope. Severe: soil texture. Severe: soil texture. Severe: soil texture. Moderate: soil texture, Moderate: soil texture. Severe: soil texture. Moderate: slope; soil texture. Moderate: slope; soil texture. Moderate: slope; soil texture. Moderate: soil texture. Moderate: soil texture. Moderate: slope; soil texture. TABLE 8.--DEGREE AND KIND OF LIMITATION FOR SPECIFIED RECREATIONAL USE--CONTINUED Soil Jaucas: Lavallee: Leveled clayey land: Lc. Leveled marly land: Lm, Leveled rocky land: Lr. Limestone rock land: Ls. Made land: Ma----- Magens: MgF------- Parasol: Rock land. No interpreta- tions. San Anton: JuB------- LaB----- Severe: poor trafficability; low productivity. Severe: coarse fragments. Severe: low pro- ductivity. Severe: low pro- ductivity. Severe: low pro- ductivity. Severe: low pro- ductivity; slope. Severe: low pro- ductivity. Severe: slope---- Moderate: slope-- Moderate: slope-- Severe: slope---- Slight----------- Moderate: slope-- Slight----------- Moderate: slope-- Severe: slope---- Severe: slope---- Severe: soil texture. Moderate: coarse fragments. Severe: soil texture. Moderate: soil texture. Very severe: rockiness. Very severe: rockiness. Severe: soil texture. Severe: slope--- Moderate: soil texture. Moderate: slope; soil texture. Moderate: slope; soil texture. Moderate: slope; soil texture. Severe: flood- ing. Moderate: slope. Moderate: soil texture. Moderate: slope; soil texture. Severe: soil texture. Moderate: soil texture. Severe: soil texture. Moderate: soil texture. Severe: rocki- ness. Severe: rocki- ness. Severe: soil texture. Severe: slope---- Moderate: soil texture. Moderate: slope; soil texture. Moderate: slope; soil texture. Moderate: slope; soil texture. Moderate: flood- ing. Moderate: slope-- Moderate: soil texture. Moderate: slope; soil texture. Intensive play Golf fairways Campsites Picnic areas areas Severe: soil texture. Severe: coarse fragments. Severe: soil texture. Moderate: soil texture. Very severe: rockiness. Very severe: rockiness. Severe: soil texture. Severe: slope--- Moderate: slope; soil texture. Severe: slope--- Severe: slope--- Severe: slope--- Severe: flood- ing. Severe: slope--- Moderate: slope; soil texture. Severe: slope--- Severe: slope--- |Severe: slope----| Severe: slope--- Severe: slope---|Severe: slope----|Severe: slope--- Paths and trails Severe: soil texture. Moderate: soil texture. Severe: soil texture. Moderate: soil texture. Severe: rocki- ness. Severe: rocki- ness. Severe: soil texture. Severe: slope. Moderate: soil texture. Moderate: soil texture. Moderate: soil texture. Moderate: slope; soil texture. Moderate: flood- ing. Moderate: soil texture. Moderate: soil texture. Moderate: soil texture. Moderate: slope; soil texture. Severe: slope. 67 TABLE’ 8.--DEGREE AND KIND OF LIMITATION FOR SPECIFIED RECREATIONAL USE--CONTINUED Intensive play Golf fairways Campsites Picnic areas areas Severe: slope; rockiness. Paths and trails Southgate: cont. Severe: rocki- ness. Severe: slope; rockiness. Severe: slope; rockiness. Severe: slope; coarse fragments. For Rock land part of SrF, see Rock land. Very severe: flooding. Very severe: flooding. Tidal flats: Tf£----|Severe: poor trafficability. Very severe: flooding. Severe: flood- ing. Very severe: flooding. Very severe: Tidal swamp: Ts----|Severe: poor flooding. trafficability. Very severe: flooding. Severe: flood- ing. Victory: VcD-------------- Severe: slope----|Moderate: slope;|Moderate: slope; |Severe: slope---|Moderate: slope; soil texture. soil texture. soil texture. VcE-------------- Severe: slope----|Severe: slope---| Severe: slope----|Severe: slope---jModerate: slope; soil texture. Severe: rocki- ness. Severe: rocki- ness. Very severe: rockiness. Volcanic rock land:|Severe: coarse fragments; slope. Very severe: rockiness. 68 FORMATION AND CLASSIFICATION OF THE SOILS Earth, the fifth largest planet in the solar sys- tem, may be compared with a huge ball of rock and water surrounded by air. The earth is very old, perhaps 5 billion years. During its existence, it has been visited by cataclysmic storms, earthquakes, and volcanic eruptions. By what may have been a series of volcanic ac- tions in a part of earth's water area--the Atlantic Ocean--basal rocks of the Virgin Islands were de- posited. These rocks have been altered by addition- al intrusions of igneous rocks, by faulting, fold- ing, and uplifting, and by the formation of wavecut terraces. In places, mainly on the island of St. Croix, limestone has formed through the accumulation of shells and coral. Throughout the time that the surface of the is- lands has been exposed, the rocks have been subject- ed to breakdown by physical and chemical processes. Along with these processes, called weathering, soil formation began. Through physical weathering, rocks were broken into smaller particles and additional surfaces were exposed. Plants, mostly lichens and mosses, grew on rock surfaces. Later they were joined by higher plants, the roots of which pried into crevices of the rocks and contributed further to physical weath- ering. Earthworms and larger burrowing animals mixed and exposed additional rock material. Chemical weathering of the rocks took place con- currently with physical weathering. As weathering continued, plant and animal growth accelerated and a variable mixture of unconsolidated mineral matter and plant and animal tissues in different stages of decomposition accumulated on the rocks. This col- lection of material is known as soil. The properties of soil are determined by the in- teraction of the five soil-forming factors--parent material, climate, living matter, relief, and time. Differences among soils are the result of differ- ences in the effects of the various soil-forming factors. Each body of soil has thickness, breadth, and length. A single unit of this three-dimensional body is called an individual soil. It ranges in size from a few square yards to several hundred acres. Individual soils that have similar charac- teristics within defined ranges make up a soil se- ries. In the Cramer series, for example, the allow- able range in depth to hard rock is 10 to 20 inches. Thus, an individual soil that is more than 20 inches deep over hard rock is excluded from the Cramer series. A phase is a subdivision of a soil series that is important for interpretation. Sometimes the allow- able range of a characteristic for a series is too wide to meet the need of the person using the soil map. For example, a slope range of gently sloping to steep is too wide a range for a farmer, for he needs to manage steep areas differently from gently sloping areas. The Cramer series is separated into phases on the basis of slope and on the basis of coarse fragments on the surface. 382-314 O- 70-6 A soil type is a kind of phase of a series. It is based on the textural class name, or on the rela- tive amounts of sand, silt, and clay in the upper- most 7 or 8 inches. Cramer clay loam, for example, is a soil type. In making the soil map of the Virgin Islands, significant phases of the different soil series were classified and mapped. Each area on the map was given a name. This name is that of the principal soil in the unit, but other soils can be present. Because of limitations in the map scale and degree of accessibility, one cannot always map out sepa- rately these tiny areas of different soils. Factors of Soil Formation The five major factors that affect soil formation are plants and animals, climate, parent material, relief, and age of landform. These factors are de- scribed in the following paragraphs. Plants and Animals Gains in organic matter, gains or losses in plant nutrients, and changes in structure and porosity are among the changes brought about by plants and animals. Plants help in the formation of soils by sending their roots into the earthy parent material. Plant roots, even though small, are strong. They tend to break up the soil, rearrange the soil particles, force openings into the lower parts of the soil, and modify porosity. Animals burrow beneath the surface and mix the soil. Earthworms, ants, and many other animals and insects are active in the soils of the Virgin Islands. ‘In a warm tropical climate, the biological activity is continuous. When plants and animals die, their remains decay and form humus in the soil. The natural vegetation on the islands varies ac- cording to the location. The mountainous region in the northwestern part of St. Croix supports fairly dense tropical forest, some parts of which have never been cleared. The trees are not large, but the undergrowth consists of thorny bushes and shrubs. In other mountainous areas there is a dense growth of thorny bushes and cactus, which is the type of vegetation typical of semiarid regions that have low rainfall and high evaporation. The soils that formed under forest vegetation have a moderate to large supply of organic matter. Grass vegetation has influenced several areas on the islands, partic- ularly on the coastal plain. The soils that formed under grass have a large supply of organic matter and are dark colored. Climate The climate is warm and dry. The amount or rain- fall differs in different locations on the islands but alone does not account for differences among 69 soils. There are only small variations in tempera- ture, no more than 5° or 7° between the coldest and the warmest months. The average annual temperature is 79.7° F. The average temperature in January is 76.9°, and that in July is 82.6°. This warm climate promotes rapid soil development. The warm tempera- ture encourages chemical reaction. Plant and animal remains decompose rapidly. Soil development is hastened further because this activity goes on throughout the year. Rainfall is limited. The amount is not enough to dissolve and remove bases and nutrients from the soil profile. Parent Material Most soils on the Virgin Islands formed in mate- rial derived in place from basic volcanic rocks. These rocks are fine grained and are high in bases, such as calcium, magnesium, sodium, and potassium. Thus, the soils are fine textured, generally clays and clay loams, and are well supplied with bases and nutrients. Cramer, Descalabrado, Victory, and Doro- thea soils are examples of soils that formed in this kind of parent material. Some soils on the islands formed in sediments de- rived in place from soft limestone. These soils, for example, Aguilita, Fredensborg, and Sion soils, are fine textured, mainly clays and clay loams. They have a dark-colored surface layer, are weakly developed, and are shallow over soft, marly lime- stone. Still other soils formed in sediments derived from volcanic or limestone rocks. These soils are strongly influenced by the physical, chemical, and mineralogical nature of the earthy parent material. Fraternidad and Aguirre soils, for example, which formed in clayey sediments high in montmorillonite, have a high shrink-swell potential. Basic volcanic rocks decompose and form soil ma- terial more rapidly than limestone rocks do. All other factors of soil formation being equal, soils that formed in material derived from volcanic rocks are better developed than those that formed in mate- rial derived from limestone. Relief The shape of the landscape influences soil forma- tion because it affects drainage, erosion, plant cover, and soil temperature. Many soils of the Vir- gin Islands are on steep slopes and therefore are subject to rapid runoff during tropical storms. They do not absorb much of the rainfall that falls on them, nor do they receive extra runoff from sur- rounding areas. The soils on foot slopes and allu- vial fans, in contrast, receive their share of rain- fall in addition to excess runoff from the surround- ing hills. Accordingly, the soils on steep slopes, even those not under cultivation, are influenced by geologic erosion. Soil material is moved downslope and is deposited on foot slopes and alluvial fans. The soils on steep side slopes of the mountains and hills, Descalabrado and Cramer soils, for example, are shallow over bedrock. The soils on foot slopes, Jacana and Isaac soils, for example, are moderately 70 deep over rock. The soils on alluvial fans, Frater- nidad, Aguirre, and Glynn, as examples, formed in sediments transported from the hills and mountains and are very deep. Age of Landform Time is required for soil formation--usually long periods. The length of time that soil-forming forces have been able to act on parent material is commonly reflected in the characteristics of the soil. The soils of the Virgin Islands range from young soils that have little or no development to old soils that have pronounced development. San Anton clay loam is an example of a young soil. It retains most of the characteristics of its parent material, except for a darkening of the sur- face layer and a weakly developed subsoil. The earthy sediments have been transported recently and deposited on the flood plains. Glynn clay loam is an example of an older soil that formed in the same kind of parent material. It has a clayey, well-de- veloped subsoil that bears little resemblance to the original parent material. Glynn soils formed on al- luvial fans. Magens soils are the oldest soils on the islands. They are acid and are low in extracta- ble bases. Their thick, red subsoil indicates that they have been exposed to the soil-forming processes for a long period. The age of a landform is influenced by the topog- raphy. Steep side slopes are usually youthful. Ge- ologic and accelerated erosion remove soil material and offset the soil-forming processes. The soils are therefore young and are shallow over rock. Des- calabrado, Southgate, and Victory soils are examples of soils that formed on steep side slopes. ‘Répresentative Soil Horizons The action of the soil-forming factors is re- flected in the soil profile, which is a succession of horizons, or layers, that extends from the surface down to the unaltered parent material. The horizons differ in one or more properties, such as color, texture, thickness, structure, consistence, porosi- ty, and reaction. The main layers used in classifying the soils of the Virgin Islands are mollic epipedons, ochric epipedons, cambic horizons, and argillic horizons. A mollic epipedon is a thick, dark-colored layer at the surface that is much like the surface layer of soils that formed under grass. This layer may have moderate to strong structure, a base saturation of 50 percent or more, and calcium as the dominant metallic cation. Aguilita, Sion, Fredensborg, Coamo, Cramer, and Pozo Blanco soils have a mollic epipedon. An ochric epipedon is a layer at the surface that contains some organic matter, but is too light color- ed or too thin to meet the requirements of other kinds of epipedons. Dorothea and Victory soils have an ochric epipedon. A cambic horizon is a subsurface horizon that has been altered but that shows no evidence of accumu- lated iron or aluminum. Victory, Southgate, Descal- abrado, and San Anton soils have a cambic horizon. An argillic horizon is one in which silicate clay has accumulated. Glynn, Coamo, Isaac, Parasol, Cra- mer, and Dorothea soils have an argillic horizon. Some soils on the islands, Sion, Fredensborg, and Fraternidad soils, for example, have neither a cam- bic nor an argillic horizon. Classification of the Soils Classification consists of an orderly grouping of soils according to a system designed to make it eas- ier to remember soil characteristics and interrela- tionships. Classification is useful in organizing and applying the results of experience and research. Soils are placed in narrow classes for discussion in detailed soil surveys and for application of knowl- edge within farms and fields. The many thousands of narrow classes are then grouped into progressively fewer and broader classes in successively higher categories, so that information can be applied to large geographic areas. Two systems of classifying soils have been used in the United States in recent years. The older system was adopted in 1938 (2) and revised later (4). The system currently used by the National Co- -operative Soil Survey was adopted in 1965 (6). It is under continual study. Readers interested in the development of the system should refer to the latest literature available (3). The current system of classification has six categories. Beginning with the most inclusive, these categories are the order, the suborder, the great group, the subgroup, the family, and the se- ries. The criteria for classification are soil properties that are observable or measurable, but the properties are selected so that soils of similar genesis are grouped together. The placement of some soil series in the current system of classification, particularly in families, may change as more precise information becomes available. Table 9 shows the classification of each soil se- ries represented on the islands by family, subgroup, and order, according to the current system. Following are brief descriptions of each of the categories in the current system, Order.--Ten soil orders are recognized in the current system. They are Entisols, Vertisols, In- ceptisols, Aridisols, Mollisols, Spodosols, Alfi- sols, Ultisols, Oxisols, and Histosols. The proper- ties used to differentiate the soil orders are those that tend to give broad climatic groupings of soils. Two exceptions are Entisols and Histosols, which oc- cur in many different climates. Suborder.--Each order is divided into suborders, primarily on the basis of soil characteristics that produce classes having genetic similarity. A subor- der has a narrower climatic range than an order has. The criteria for suborders reflect either the pres- ence or absence of waterlogging or differences in climate or vegetation. Great _group.--Each suborder is divided into great groups on the basis of uniformity in the kind and sequence of genetic horizons. Subgroup.--Each great group is divided into sub- groups, one representing the central (typic) segment of the group, and others, called intergrades, made up of soils that have mostly properties of one great group but also one or more properties of another great group. Family.--Families are established within each subgroup, primarily on the basis of properties im- portant to plant growth. Some of these properties are texture, mineralogy, reaction, soil temperature, permeability, consistence, and thickness of hori- zons. Series.--The series has the narrowest range of characteristics of the categories in the classifica- tion system. It is explained in the section "How This Survey Was Made." A detailed description of each soil series repre- sented on the islands is given in the section "De- scriptions of the Soils." 71 Series TABLE 9.--SOIL SERIES CLASSIFIED ACCORDING TO THE CURRENT SYSTEM OF CLASSIFICATION Loamy-skeletal, carbonatic, isohyperthermic--|Typic Rendolls----------------- Fine, mixed, isohyperthermic----------------- Udic Pellusterts--------------- Fine, mixed, isohyperthermic----------------- Udic Argiustolls--------------- Fine-loamy, mixed, isohyperthermic----------- Fluventic Ustropepts----------- ween - ne ------- Lithic Argiustolls------------- Lithic Vertic Ustropepts-----~-- Mollisols. Vertisols. Mollisols,. Inceptisols. Mollisols. Inceptisols. Diamond--------| Fine-loamy, mixed, isohyperthermlc----------- Lithic Ustropepts-------------- Inceptisols. Dorothea-------| Fine, mixed, isohyperthermic----------------- Udic Haplustalfs--------------- Alfisols. Fraternidad----| Very fine, montmorillonitic, isohyperthermic-|Udic Chromusterts-------------- Vertisols. Fredensborg----| Fine, carbonatic, isohyperthermic------------ Typic Rendolls----------------- Mollisols. Glynn---------- Fine, mixed, isohyperthermic-------~---------- Typic Haplustalfs-------------- Alfisols. Hesselberg-----| Clayey, mixed, isohyperthermic, shallow------ Petrocalcic Paleustolls-------- Mollisols. Isaac---------- Fine, mixed, isohyperthermic----------------- Udic Argiustolls--------------- Mollisols. Jacana--------- Fine, mixed, isohyperthermic----------------- Vertic Ustropepts-- tiated -----|Inceptisols. Jaucas~--------- Carbonatic, isohyperthermic------------------ Typic Ustipsamments------------ Entisols. Lavallee------- Fine-loamy, mixed, isohyperthermic----------- Udic Haplustalfs--------------- Alfisols. Magens--------- Clayey, oxidic, isohyperthermic-------------- Oxic Tropustults--------------- Ultisols. Parasol-------- Fine-loamy, mixed, isohyperthermic----------- Udic Argiustolls--------------- Mollisols. Pozo Blanco----| Fine-loamy, carbonatic, isohyperthermic------ Typic Calciustolls------------ Mollisols. San Anton------ Fine-loamy, mixed, isohyperthermic----------- Cumulic Haplustolls---------- Mollisols. Sion----------- Fine-loamy, carbonatic, isohyperthermic-----~- Typic Rendollis----------------- Mollisols. Southgate------ Loamy-skeletal, mixed, isohyperthermic------- Lithic Ustropepts--------------|Inceptisols. Victory-------- Fine-loamy, mixed, isohyperthermic----------- Typic Ustropepts-~-------------- Inceptisols. 72 ADDITIONAL FACTS ABOUT THE ISLANDS The acreage on the Virgin Islands that was once typically rural is rapidly decreasing with increas- ing development of residential, recreational, trans- portational, commercial, and industrial facilities. This change, particularly in residential develop- ment, began soon after the end of World War II and is likely to continue for many years. People from the States are migrating to the islands, and local residents whose standard of living is now somewhat higher are building new homes. Rapid urban expansion has increased the need for new roads, new schools, and new recreational devel- opments and has intensified the limitations that al- ready existed, among them, a limited water supply and an inadequate system for sewage disposal. For many years the sugarcane grown on St. Croix was an important part of the economy, but since the major sugar mill has ceased operations, sugarcane is no longer the most important crop. Finding a suita- ble cash crop to replace sugarcane is difficult be- cause there is no water for irrigation. Climate 4 The Virgin Islands of the United States extend eastward from Puerto Rico, along the path of the Lesser Antilles, directly in the belt of subtropi- cal, easterly trade winds. The climate is maritime tropical, one of the most equable in the world. It is characterized by generally fair weather, steady winds, and slight but regular annual, seasonal, and diurnal ranges of temperature. A significant fea- ture of the rainfall pattern is the marked variation within short distances with change in terrain and elevation. Minor seasonal contrasts are generated by out- breaks of cold air from the higher latitudes in win- ter and by tropical disturbances late in summer and in fall. Of greater significance is the diurnal tempering effect of the islands on the surrounding ocean climate. Since the land area is small, the Virgin Islands exert less modification on the sur- rounding ocean climate than do the islands of the Greater Antilles, which lie to the west. Table 10 shows, by months, the average daily maxi- mum temperature, the average daily minimum tempera- ture, and the average precipitation on St. Croix. Rainfall.--Lifting of moist air over hilly terrain is the most common cause of rainfall on the islands. The amount of rainfall increases with increasing elevation, The average annual total at the higher elevations is between 50 and 60 inches, and at the lower elevations, between 20 and 30 inches. Whether an exposure is on the windward or the leeward side of a slope is a significant fac- tor in the amount of rainfall received. In general, there is a much higher occurrence of rainfall by day than by night. 4ay Robert J. Calvesbert, climatologist, Weather Bureau, ESSA. and the next day 15 miles per hour. There is no sharply defined wet season or dry season on the islands. Records indicate seasons much like those along the southern coast of Puerto Rico. The rainfall is lightest during the period December through June. On St. Thomas and St. John, it is generally lightest in February and March and heaviest in September and October. On St. Croix, it is heaviest in September, October, and November. The number of days with rainfall equal to or more than one-tenth of an inch ranges from about 75 to 110, depending on location. Temperature.--Variations in temperature between the coolest and the warmest months are 5 to 7 de- grees at the most. The highest temperatures are in August, and the lowest in January or February. Dur- ing the warmest months, the highest average daytime temperature is about 87° F. During hot spells, which occur nearly every year, the temperature ex- ceeds 88° or 90° for several days in succession. The average lowest nighttime temperature during the warmest months is between 74° and 78°. Nighttime temperatures are somewhat lower at the higher eleva- tions. During the coldest months, the highest tem- perature is generally in the low 80's, and the low- est in the high 60's or low 70's. At the higher elevations, outbreaks of cold air into the Caribbean bring nighttime temperatures down to the low 60's or high 50's, Wind.--Regularity in direction of the trade winds is one of the most dependable weather phenomena on the islands. Almost without exception the trade winds blow from an easterly direction. The velocity varies daily; one day it averages 5 miles per hour, A velocity of more than 15 miles per hour occurs more frequently in winter than in other seasons. Leeward slopes are protected against the full force of the trade winds, but the flow is strong enough to pass over the high- er terrain without diminishing in velocity. Most locations have a good flow of air movement most of the day. On the nearly level parts of St. Croix, windbreaks are needed to protect garden crops and young fruit trees. The nighttime offshore land breeze and the daytime onshore sea breeze that are typical of Puerto Rico are lacking on the Virgin Islands because of the small total land area, but the diurnal variation in windspeed, that is, the calms and low speeds at night and the increase in velocity at daybreak, provides somewhat the same effect in physical comfort. Hurricanes and tropical storms.--The islands are affected occasionally by tropical storms and hurri- canes. They lie outside the main paths of severe tropical disturbances except those that occur from August through the first half of October. The storms that develop over the South Atlantic: east of the Antilles chain usually move toward the north or north- west and pass north or south of the islands; rarely do they pass ‘directly over them. There is risk of hurricane force winds about once every 9 or 10 years. 73 TABLE 10.--TEMPERATURE AND PRECIPITATION [Data from Alexander Hamilton Field, St. Croix] One year in 10 will have-- In. Average number of days with more than one-tenth of an inch of rainfall Average | Average daily daily | Average | Average | Average maximum | minimum | maximum | minimum January ---- 2.23 7.2 5 February --- 2.19 5.8 6 March------ 1.73 4.6 4 April------ 2.83 7.6 6 May -------- 4.31 8.2 8 June------- 3.10 6.0 9 July------- 3.51 6.6 8 August----- 4.58 8.8 9 September-- 6.65 11.0 10 October---- 5.45 10.2 8 ‘November--- 4.65 9,0 9 December--- 3.34 8.6 9 Year---- 44. 53.8 91 1 average annual highest temperature. 2 average annual lowest temperature. 74 Evaporation.--The steady flow of trade winds and the warm temperature result in high evaporation rates, Open-pan measurements taken at Annas Hope indicate rates that exceed the average annual rain- fall. Following is the potential evapotranspira- tion, that is, the amount of moisture lost through evaporation and transpiration, as estimated by the Thornthwaite formula, in inches of water each month. Month: Inches January--~--------------------------- 3,89 February -----------------~----+--+---- 3.67 March------------------------------- 4.45 April------------------------------- 4.96 May- -------------------------------- 5.94 June -------------------------------- 6.27 July ---------------------------+-+-+-- 6.55 August ---~---------~------~--+--------- 6.40 September- ------~------------------- 5.85 October--------------------------+--- 5.69 November---------------------------- 4.90 December----~--------~-------~--------- 4,27 Annual~-------------- wooo rennneH- 62.78 Drought .--Periods of deficient rainfall occur al- most every year in some parts of the Virgin Islands. Although some of these periods are of short dura- tion, they have a serious impact on farming and dairying activities, on the urban water supply, and on the general economy. The islands have no large rivers and no large storage reservoirs. Consequent- ly, even a few months of drought can be damaging. Droughts are most prevalent late in fall, in winter, and early in spring. The severity of drought on the islands has been computed by the Palmer Index, developed by the Envi- ronmental Data Service. This computation is based on the difference between the amount of rainfall re- ceived and the amount needed to maintain an average for the area. It indicates that mild to extreme droughts can be expected about half the time, severe to extreme droughts about 15 percent of the time, and mild to moderate droughts about a third of the time. Since 1931, there have been 14 droughts in- dexed by the Palmer system. The longest was for 48 months, from February 1945 to February 1949. The drought of 1964-65 was the most recent and the most severe, Relative humidity.--The average relative humidi- ty, over a 6-year period, at Alexander Hamilton Field on St. Croix is summarized, by months, in the following tabulation. The values shown are also representative of Truman Field on St. Thomas. Average relative humidity Atlantic standard time Month: 2:30 a.m 2:30 p.m January ~-------~--- 8l 66 February-~-------- 84 63 March------------ 83 63 April------------ 85 66 May -------------- 87 70 June------------- 84 69 Average relative humidity Atlantic standard time (Continued) Month 2:30 a.m. 2:30 p.m July------------- 86 70 August~---------- 87 69 September-------- 88 73 October---------- 90 72 November~---~~--- 90 72 December--------- 86 69 Annual ------- 86 69 The relative humidity at these two locations is somewhat lower than that at San Juan, Puerto Rico, but it is sufficiently high, along with the salt content of the air, to cause corrosion and deterior- ation of buildings and metal equipment. Water Supply The greatest problem confronting farmers on the islands is that of retaining sufficient soil mois- ture to produce crops that are otherwise suited to the soils and the climate. Drought is more serious now than ever before in history. Many springs and wells have gone dry. Subterranean reservoirs have become more and more depleted, even though, accord- ing to records, the islands receive about the same amount of rainfall as at any time in the past. Depletion of the underground water supply is the result of poor soil management. Large areas have been cleared of the original forest cover, subse- quently cultivated, and then abandoned. Consequent- ly, most of the moisture is lost through runoff and evaporation. Only a small amount is absorbed. Natural Vegetation The vegetation now growing on the islands differs from the original vegetation and differs somewhat in different parts. Uncleared mountainous areas sup- port a fairly dense growth of tropical forest, in- ‘cluding a few large trees and a dense undergrowth of brush and vines, but the cleared mountainous areas are covered with thorny brush, which is of little or no value. Much of the cultivated acreage on the coastal plain has been converted to rangeland. The vegeta- tion is mainly cactus and small thorny brush. There is very little pasture grass. Hurricanegrass, which is considered to be an inferior pasture grass, has spread rapidly over the southern part of the coastal plain and into adjacent mountainous areas. Hilly areas between the coastal plain and the mountains are covered with thorny brush and poor- quality pasture grass. There are only a few trees. The eastern ends of the islands, which are usually drier than other parts, are covered with a dense growth of cactus and thorny brush. The abundance of cactus and thorny brush is the result of overgrazing and improper use of the soils. Guineagrass could be established if the areas form- erly cleared and cultivated were cleared of brush and brought under good management. 75 LITERATURE CITED (1) American Association of State Highway Officials. 1961. Standard Specifications for Highway Materials and Methods of Sampling and Test- ing. Ed. 8, 2 v., illus. (2) Baldwin, Mark, Kellogg, Charles E., and Thorp, James. 1938. Soil Classification. Ybk., pp. 970-1001, illus. (3) Simonson, Roy W. ; 1962. Soil Classification in the United States. Sci. 137: 1027-1034, illus. U.S. Dept. Agr. (4) Thorp, James, and Smith, Guy D. 1949. Higher Categories of Soil Classifica- tion: Order, Suborder, and Great Soil © Groups. Soil Sci. 67: 117-126. 76 (S) United States Department of Agriculture. 1951. Soil Survey Manual. U.S. Dept. Agr. Handbook No. 18, 503 pp., illus. (6) 1960. Soil Classification, A Comprehensive System, 7th Approximation. 265 pp., illus. [Supplement issued in March 1967] (7) Waterways Experiment Station, Corps of Engi- neers. 1953. The Unified Soil Classification Sys- tem. Tech. Memo. 3-357, 2 v. and app. [Revised in 1957} GLOSSARY Alluvium. Soil material, such as sand, silt, or clay, that has been deposited on land by streams. Calcareous soil. A soil containing enough calcium carbonate (often with magnesium carbonate) to effervesce (fizz) visibly when treated with cold, dilute hydrochloric acid. As a soil separate, mineral soil particles that are less than 0.002 millimeter in diam- eter. As a soil textural class, soil material that is 40 percent or more clay, less than 45 percent sand, and less than 40 percent silt. (See also Texture, soil.) Concretions. Grains, pellets, or nodules that con- sist of concentrations of compounds or of soil grains cemented together. They are of various sizes, shapes, and colors. The composition of some concretions is unlike that of the sur- rounding soil. Calcium carbonate and iron ox- ide are examples of material commonly found in concretions. Consistence, soil. The feel of the soil and the ease with which a lump can be crushed by the fingers. Terms commonly used to describe con- sistence are-- Loose,--Noncoherent when dry or moist; will not hold together in a mass. Friable.--When moist, crushes easily under gentle pressure between thumb and forefinger and can be pressed together into a lump. Firm.--When moist, crushes under moderate pres- sure between thumb and forefinger, but re- sistance is distinctly noticeable. Plastic.--When wet, readily deformed by moderate pressure but can be pressed into a lump; will form a "wire" when rolled between thumb and forefinger. Sticky.--When wet, adheres to other material, and tends to stretch somewhat and pull apart rather than to pull free from other mate- rial. Hard.--When dry, moderately resistant to pres- sure; can be broken with difficulty between thumb and forefinger. Soft.--When dry, breaks into powder or individual grains under very slight pressure. Cemented.--Hard and brittle; little affected by moistening. Erosion. The wearing away of the land surface by wind, running water, and other geological agents. Flood plain. Nearly level land, consisting of stream sediments, that borders a stream and is subject to flooding unless protected artifi- cially. Horizon, soil. A layer of soil, approximately par- allel to the surface, that has distinct char- acteristics produced by soil-forming proc- esses. These are the major horizons: O horizon.--The layer of organic matter on the surface of a mineral soil. This layer con- sists of decaying plant residues. Clay. A horizon.--The mineral horizon at the surface or just below an O horizon. This horizon is the one in which living organisms are most active and therefore is marked by the accu- mulation of humus. The horizon may have lost one or more of soluble salts, clay, or sesquioxides (iron and aluminum oxides). B horizon.--The mineral horizon below an A hori- zon. The B horizon is in part a layer of change from the overlying A to the under- lying C horizon. The B horizon also has distinctive characteristics caused (1) by accumulation of clay, sesquioxides, humus, or some combination of these; (2) by pris- matic or blocky structure; (3) by redder or stronger colors than the A horizon; or (4) by some combination of these. Combined A and B horizons are usually called the so- lum, or true soil. If a soil lacks a B horizon, the A horizon alone is the solun,. C horizon.--The weathered rock material immedi- ately beneath the solum. In most soils this material is presumed to be like that from which the overlying horizons were formed. If the material is known to be different from that in the solum, a Roman numeral precedes the letter C. R layer.--Consolidated rock beneath the soil. The rock usually underlies a C horizon but may be immediately beneath an A or B hori- zon. Mottling, soil. Irregular marking with spots of different colors that vary in number and size. Mottling in soils usually indicates poor aera- tion and lack of drainage. Descriptive terms are as follows: Abundance--few, common, and many; size--fine, medium, and coarse; and con- trast--faint, distinct, and prominent. The size measurements are these: fine, less than 5 millimeters (about 0.2 inch) in diameter along the greatest dimension; medium, ranging from 5 millimeters to 15 millimeters (about 0.2 to 0.6 inch) in diameter along the great- est dimension; and coarse, more than 15 milli- meters (about 0.6 inch) in diameter along the greatest dimension. Permeability. The capacity of the soil to transmit air or water. Terms used to describe permea- bility are as follows: very slow, slow, mod- erately slow, moderate, moderately rapid, rapid, and very rapid. pH value. A numerical means for designating acidity and alkalinity in soils. A pH value of 7.0 indicates precise neutrality; a higher value alkalinity; and a lower value, acidity. (See also Reaction, soil.) Profile, soil. A vertical section of the soil through all its horizons and extending into the parent material. Reaction, soil. The degree of acidity or alkalinity of a soil, expressed in pH values or words as follows: 77 Extremely acid---------------- eeeen---- Below 4.5 Very strongly acid-------------------- 4.5 to 5.0 Strongly acid------------------=------- 5.1 to 5.5 Medium acid--------------------------- 5.6 to 6.0 Slightly acid------------------------- 6.1 to 6.5 Neutral -------------+------------------ 6.6 to 7.3 Mildly alkaline----------~+------------ 7.4 to 7.8 Moderately alkaline------------------- 7.9 to 8.4 Strongly alkaline--------------------- 8.5 to 9.0 Very strongly alkaline---------------- 9.1 and higher Sand. As a soil separate, individual rock or miner- al fragments 0.05 millimeter to 2.0 millime- ters in diameter. Most sand grains consist of quartz, but sand may be any mineral composi- tion. As a textural class, soil that is 85 percent or more sand and not more than 10 per- cent clay. (See also Texture, soil.) Saprolite. Thoroughly decomposed, soft, earthy, un- transported rock. Silt. As a soil separate, individual mineral parti- cles that range in diameter from the upper limit of clay (0.002 millimeter) to the lower limit of very fine sand (0.05 millimeter). As a textural class, soil that is 80 percent or more silt and less than 12 percent clay. (See also Texture, soil.) Solum. The upper part of a soil profile, above the Structure, soil. particles into compound particles or clusters 78 parent material, in which the processes of soil formation are active. The solum in ma- ture soil includes the A and B horizons. Gen- erally, the characteristics of the material in these horizons ‘are unlike those of the under- lying material. The living roots and other plant and animal life characteristic of the soil are largely confined to the solum. The arrangement of primary soil that are separated from adjoining aggregates and have properties unlike those of an equal mass of unaggregated primary soil particles. Subsoil. Terrace (geologic). Texture, soil. Tilth, Water The principal forms of soil structure are-- platy (laminated), prismatic (vertical axis of aggregates longer than horizontal), colum- nar (prisms with rounded tops), blocky (angu- Tar or subangular), and granular. Structure- less soils are (1) single grain (each grain by itself, as in dune sand) or (2) massive (the particles adhering together without any regu- lar cleavage, as in many claypans and hard- pans). Technically, the B horizon; roughly, the part of the profile below plow depth. An old alluvial plain, ordinar- ily flat or undulating, bordering a river, a lake, or the sea. Stream terraces are fre- quently called second bottoms, as contrasted to flood plains, and are seldom subject to overflow.’ Marine terraces were deposited by the sea and are generally wide. The relative proportions of sand, silt, and clay particles in a mass of soil. The basic textural classes, in order of in- creasing proportion of fine particles, are sand, loamy sand, sandy loam, loam, silt loam, sandy clay loam, clay loam, silty clay sandy clay, silty clay, and clay. The sand, loamy sand, and sandy loam classes may be further divided by adding the words "coarse," "fine," or "very fine'' to the name of the textural class. soil. The condition of the soil, especially as to soil structure, in relation to the growth of plants. Good tilth refers to the friable state and is associated with high non- capillary porosity and stable, granular struc- ture. A soil in poor tilth is nonfriable, hard, nonaggregated, and difficult to till. table. The highest part of the soil or under- lying rock material that is wholly saturated with water. In some places an upper, or perched, water table may be separated from a lower one by a dry zone. GUIDE TO MAPPING UNITS For complete information about a mapping unit, read both the description of the mapping unit and that of the soil series to which the mapping unit belongs. For complete information about a capability unit, read the introduction "Use of the Soils for Crops and Pasture," which gives general information about management. All woodland groups are described on page 46. Other information is given in tables as follows: Acreage and extent, table 1, page 7; Use of the soils in engineering, table 5, Use of the soils for recreational _estimated yields, table 2, page 38. page 48, table 6, page 54, table 7, development, table 8, page 65. page 62. Capability Woodland Described unit Range site group Map on symbol Mapping unit page Symbol Page| Name AgB Aguilita gravelly clay loam, 2 to 5 percent slopes------ 6 IVe-1 Shallow (6,9) 2 AgC2 Aguilita gravelly clay loam, 5 to 12 percent slopes, eroded------------------------------------------------ 6 VIe-3 Shallow (6,9) 2 AgD Aguilita gravelly clay loam, 12 to 20 percent slopes---- 8 VIe-3 35 Shallow (6,9) 44,45 2 AgE Aguilita gravelly clay loam, 20 to 40 percent slopes---- 8 VIlIe-1 36 | Shallow (6,9) 44,45 2 AgF <Aguilita gravelly clay loam, 40 to 60 percent slopes---- 8 VIle-1 36 | Shallow (6,9) 44,45 2 AuA Aguirre clay, 0 to 2 percent slopes--------------------- 9 TVw-1 35 | Deep (4) . 44 - CaB- Coamo clay loam, 2 to 5 percent slopes------------------ 10 IIIe-1 34 Deep (1,4,7) 39,44 - Cb Cobbly alluvial land------------------------------------ 10 VIIs-4 37 | ------------- 0 ----- = CoA Cornhill gravelly clay loam, 0 to 2 percent slopes------ 11 IVe-1 35 Deep (4,7) 44 - Cre Cramer gravelly clay loam, S to 12 percent slopes------- 12 VIs-3 36 Shallow (6,9) 44,45 4 CrE Cramer gravelly clay loam, 12 to 40 percent slopes------ 12 VIs-3 36 Shallow (6,9) 44,45 4 CrF Cramer gravelly clay loam, 40 to 60 percent slopes------ 12 VIIs-3 36 | Shallow (6,9) 44,45 4 CsE2 Cramer stony clay loam, 12 to 40 percent slopes, eroded- 12 VIIs-1 36 | Shallow - CsF Cramer stony clay loam, 40 to 60 percent slopes--------- 12 VIIs-1 - CvE Cramer-Isaac gravelly clay loams, 12 to 40 percent slopes-~-~--~------------------------------------------- 13 VIe-1 35 | ------------- ----- 4 DeD Descalabrado clay loam, 12 to 20 percent slopes--------- 13 VIs-3 Shallow 44,45 4 (3,6,9) DeE Descalabrado clay loam, 20 to 40 percent slopes--~------- 14 VIs-3 Shallow 44,45 4 (3,6,9) DeF Descalabrado clay loam, 40 to 60 percent slopes--------- 14 VIIs-3 Shallow 44,45 4 (3,6,9) DIB Diamond-Limestone rock land complex, 0 to S percent slopes-------------------------------- 2220-2 -------- 14 VIs-2 Rough Stony 2 Land (10) D1C2 Diamond-Limestone rock land complex, $ to 12 percent slopes, eroded-~---------------------------------~------ 15 Rough Stony 2 Land (10) DoE Dorothea clay loam, 20 to 40 percent slopes--------~---- 15 Hilly Clay 44 i (2,5) DoF Dorothea clay loam, 40 to 60 percent slopes------------- 16 Hilly Clay 1 FcA Fraternidad clay, 0 to 3 percent slopes~---------------- 17 - FeC2 Fraternidad clay, 3 to 12 percent slopes, eroded-------- 17 - Fra Fredensborg clay, 0 to 2 percent slopes----------------- 18 2 FrB Fredensborg clay, 2 to 5 percent slopes---~-------- 18 2 FrC€2 Fredensborg clay, 5 to 12 percent slopes, eroded-- 18 2 GyB Glynn clay loam, 2 to 5 percent slopes------------ 19 3 GyC2 Glynn clay loam, 5 to 12 percent slopes, eroded--- 19 3 HeA Hesselberg clay, 0 to 2 percent slopes------------------ 20 Shallow (6) - IsD2 Isaac clay loam, saprolitic substratum, 12 to 20 percent slopes, eroded---------------------------------------- Pal Hilly Clay Ll (2,5,8) IsE Isaac clay loam, saprolitic substratum, 20 to 40 percent slopes-------------- +--+ 2-20 noone nn ene eee eee eee 21 Hilly Clay 1 (2,5,8) IvD Isaac gravelly clay loam, 5 to 20 percent slopes-------- 21 Hilly Clay 44 4 (2,5,8) JaB Jacana clay loam, 2 to 5 percent slopes----------------- 22 Hilly Clay 44 4 (2,5,8) U. S, GOVERNMENT PRINTING OFFICE : 1970 O - 382-314 GUIDE TO MAPPING UNITS--Continued Capability Woodland Described unit Range site group Map on symbol Mapping unit page Symbol Page | Name JaC Jacana clay loam, 5 to 12 percent slopes--~------------- 22 IVe-3 34 | Hilly Clay 4 (2,5,8) JaD Jacana clay loam, 12 to 20 percent slopes~------------- 22 VIe-1 Hilly Clay 4 (2,5,8) JuB Jaucas sand, 0 to 5 percent slopes--------------------- 23 VIIs-2 Coastal Sand - (11) LaB- Lavallee gravelly clay loam, 2 to 5 percent slopes----- 24 TIe-2 Deep (1,4) 3 Le Leveled clayey land------------------------------------ 24 VIIIs-1 - Lm Leveled marly land-------------- ee 24 VITIs-1 - Lr Leveled rocky land-------------~------+---+-+~---------- 24 VIIIs-1 - Ls Limestone rock land------------------------------------ 24 VIIIs-1 - Ma Made land---------------------------------------------- 24 VITIs-1 - MgF Magens silty clay loam, 30 to 50 percent slopes-------- 25 VIe-2 Hilly Clay 1 (2,5) PaB Parasol clay loam, 2 to 5 percent slopes--------------- 26 Tle-2 Hilly Clay 3 (2,5) PaC Parasol clay loam, 5 to 12 percent slopes-------------- 26 IITe-1 Hilly Clay 3 (2,5) PbC Pozo Blanco clay loam, 5 to 12 percent slopes---------- 27 IVe-1 Hilly Clay 2 (5,8) PbD Pozo Blanco clay loam, 12 to 20 percent slopes--------- 27 VIe-3 Hilly Clay 2 (5,8) Sad San Anton clay loam, 0 to 3 percent slopes------------- 28 IIc-1 Deep (1,4,7) 3 SaC San Anton clay loam, 5 to 12 percent slopes------------ 28 Iile-1 Deep (1,4,7) 3 ScB Sion clay loam, 0 to 5 percent slopes------------------ 29 IIIsc-1 Shallow (6) 2 ScC Sion clay loam, 5 to 12 percent slopes------~----------- 29 IVe-1 Shallow (6) 2 SgE Southgate clay loam, 12 to 40 percent slopes----------- 30 VIs-3 Shallow (6,9) 4 SgF Southgate clay loam, 40 to 60 percent slopes----------- 30 VIIs-3 Shallow (6,9) 4 SrF Southgate-Rock land complex, 20 to 60 percent slopes--- 30 VIIs-3 : Rough Stony - Land (10) Tf Tidal flats-------------------------------------------- 30 VITIw-1 - Ts Tidal swamp-------------------------------------------- 30 VITIw-1 - VcD Victory clay loam, 12 to 20 percent slopes------------- 31 VIe-1 Hilly Clay (2) VcE Victory clay loam, 20 to 40 percent slopes~------------ 31 VIe-1 Hilly Clay 1 (2) Vr Volcanic rock land------------------------------------- 31 VITIs-1 Rough Stony - Land (10) Accessibility Statement This document is not accessible by screen-reader software. 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Information about how to file a discrimination complaint is available from the Office of the Assistant Secretary for Civil Rights. USDA prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex (including gender identity and expression), marital status, familial status, parental status, religion, sexual orientation, political beliefs, genetic information, reprisal, or because all or part of an individual’s income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) To file a complaint of discrimination, complete, sign, and mail a program discrimination complaint form, available at any USDA office location or online at www.ascr.usda.gov, or write to: USDA Office of the Assistant Secretary for Civil Rights 1400 Independence Avenue, S.W. Washington, DC 20250-9410 Or call toll free at (866) 632-9992 (voice) to obtain additional information, the appropriate office or to request documents. Individuals who are deaf, hard of hearing, or have speech disabilities may contact USDA through the Federal Relay service at (800) 877-8339 or (800) 845-6136 (in Spanish). USDA is an equal opportunity provider, employer, and lender. Persons with disabilities who require alternative means for communication of program information (e.g., Braille, large print, audiotape, etc.) should contact USDA‘s TARGET Center at (202) 720-2600 (voice and TDD). U. S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE GENERAL SOIL MAP VIRGIN ISLANDS of the UNITED STATES ST. THOMAS, ST. JOHN, AND ST. CROIX ISLANDS Pelican Cay Little Hans Lollik Island 5ecricket Rock 5 Sula Cay TLANTIC Cockroach | A OCEAN Outer Brass | Inner Brass el ATLANTIC Picara Pt Tropaco Pt BPoutencar Cay Salt Cay Whistling Cay / a Congo Cay 64°50’ Mingo | Cay Lovango Cay @d 65°00! Stumpy Pt | West ay Grass 5 Little St ie PAoikun c ay Savana Island Mosquito Pt Leduck | Island Tipp ate Istana ST THOMAS | cs | Little St James | Dog Island Buck 1 5 Island | Frenchcap Cay —18° 14! Capella Islands | 64°51’ CARIBBEAN CARIBBEAN SEA SEA Buck Island 64°40’ Green Cay Sf a te Christiansted Harbor Protestant Cave] Grass Pt Vagthus Pt Krause Pt 4yieeeas C Scale 1:126720 1 0 1 2 3 4 Miles HSE Oe eS ae NOTE — This map is intended for general planning. Each delineation may contain soils having rat- ings different from those shown on the map. Use detailed soil maps for operational planning. Flanagan | SOIL ASSOCIATIONS Descalabrado-jacana association; Strongly slaping to steep, well-drained soils; clay loam to clay subsoil; shallow and moderately deep over volcanic rock; on mountainsides and foot slopes Aquilita-Fredensborg-Sion association: Gently sloping to steep, well-drained soils; clay loam and silty clay !oam material below the surface layer; shallow over soft, marly limestone; on hills, foot slopes, and terraces Fraternidad-Aguirre-Glynn association: Nearly level to gently sloping, well-drained to poorly drained, deep, mainly clayey soils on alluvial fans Southgote-Paraso! association: Steep to sloping, well-drained soils; gravelly loam to clay subsoil; shallow and deep over weathered granitic rock; on mountainsides, foot slopes, and alluvial fans Cramer-Isaoc association: Very steep to strongly sloping, well- drained soils; clayey in subsoil; shallow and moderately deep over volcanic rock; on mountainsides and foot slopes Dorothea-Victory-Magens association; Steep and very steep, well-drained, deep soils; clay to clay loam subsoil; on mountainsides Cornhill-Coamo-San Anton association: Nearly level to gently sloping, moderately well drained and well drained, deep soils; clay to clay loam subsoil; on alluvial fans and flood plains May 1969 Pelican Cay, YCricket Rock ANTIC OC gr - meee yee tana Sula Cay i Outer Brass i : & : ATLANTIC : : O Inner Brass’ picara Mt 5 Cc 34 4y Tropaco : "| Cfbutchcap Cay : pt os - ; - ; ; ; ; a a Cockroach | Stumpy Pt oe Salt Cay , <= a1 64750" Mingo . a leg Botany ~~ Fr Cay a ites Cay Little St Thomasg 54?40" = Kalkun Cay Savana Island — 18°20’ : : (Flanagan | Mpeautte Pt S i oe) CARIBBEAN SEA | Water : a 4 8 *talend bs > Sabe Istend ST THOMAS oe ee — ee PSUs ISTE , Aaa. oo | 4 3 Little St James | & Dog Island % Buck | i eee CARIBBEAN SEA i capene Islands — 18°14! 64°51! ih Be wae? 4 ay. VIRGIN ISLANDS of the UNITED STATES ST. THOMAS AND ST. JOHN ISLANDS Scale 1:126720 1 0 1 2 3 4 Miles Bae) aS ae ee eee 1 a 3 iset, sheet 22 CARIBBEAN SEs ees 1 SR ARID SEBEL SS ET REG SE ERE HES TST USS SES TGS TTT nee Saat BRST Arey pees ee: oar ALT Bek stand ; & i T i 4 i fr “T [ 64740’ } : . 4 = Green Cay, | : ‘ 64°50 ra 4 i rory : = | eA VF & ‘aisiilamesianiiaieaanigncteeiniiniiainiaiiaieiabdl ] ~ Rd Aowdl olin Nall Zanll = a ») E gre) Ne=" ee | RMT ae SE Seanad eats wo i ai oe gee ES SSE: Christiansted Harbor | INDEX TO MAP SHEETS VIRGIN ISLANDS of the UNITED STATES ST. CROIX ISLAND Scale 1:126720 1 0 1 2 3 4 Miles Cs Le arene! ee U. S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE SOIL LEGEND The first capital letter is the initial one of the soil name. A second capital letrer, A, B, C, D, E, or F, shows the slope. Most symbols without a slope letter are those of nearly level land types, but some are for land types that have a considerable range in slope. Soils that are named as eroded have a final number, 2, in their symbol. SYMBOL NAME AgB Aguilita gravelly clay loam, 2 to 5 percent slopes AgC2 Aguilita gravelly clay loam, 5 to 12 percent slopes, eroded AgD Aguilita gravelly clay loam, 12 to 20 percent slopes AgE Aguilita gravelly clay loam, 20 to 40 percent slopes AgF Aguilita gravelly clay loam, 40 to 60 percent slopes AvA Aguirre clay, 0 to 2 percent slopes CaB Coamo clay loam, 2 to 5 percent slopes Cb Cobbly alluvial land CoA Cornhill gravelly clay loam, 0 to 2 percent slopes crc Cramer aravelly clay loam, 5 to 12 percent slopes CrE Cramer gravelly clay loam, 12 to 40 percent slopes CrF Cramer gravelly clay loam, 40 to 60 percent slopes CsE2 Cramer stony clay loam, 12 to 40 percent slopes, eroded CsF Cramer stony clay loam, 40 to 60 percent slopes CvE Cramer—Isaac gravelly clay loams, 12 to 40 percent slopes DeD Descalabrado clay loam, 12 to 20 percent slopes DeE Descalabrado clay loam, 20 to 40 percent slopes DeF Descalabrado clay loam, 40 to 60 percent slopes OIB Diamond—Limestone rock land complex, 0 to 5 percent slopes DIC2 Diamond—Limestone rock land complex, 5 to 12 percent slopes, eroded DoE Dorothea clay loam, 20 to 40 percent slopes DoF Dorothea clay loam, 40 to 60 percent slopes Fraternidad clay, 0 to 3 percent slopes Fraternidad clay, 3 to 12 percent slopes, eroded Fredensborg clay, 0 to 2 percent slopes Fredensborg clay, 2 to 5 percent slopes Fredensborg clay, 5 to 12 percent slopes, eroded Glynn clay loam, 2 to 5 percent slopes Glynn clay loam, 5 to 12 percent slopes, eroded Hesselberg clay, 0 to 2 percent slopes Isaac clay loam, saprolitic substratum, 12 to 20 percent slopes, eroded Isaac clay loam, saprolitic substratum, 20 to 40 percent slopes Isaac gravelly clay loam, 5 to 20 percent slopes Jacana clay loam, 2 to 5 percent slopes Jacana clay loam, 5 to 12 percent slopes Jacana clay loam, 12 to 20 percent slopes Jaucas sand, 0 to 5 percent slopes Lavallee gravelly clay loam, 2 to 5 percent slopes Leveled clayey land Leveled marly land Leveled rocky land Limestone rock land Made land Magens silty clay loam, 30 to 50 percent slopes Parasol clay loam, 2 to 5 percent slopes Parasol clay loam, 5 to 12 percent slopes Pozo Blanco clay loam, 5 to 12 percent slopes Pozo Blanco clay loam, 12 to 20 percent slopes San Anton clay loam, 0 to 3 percent slopes San Anton clay loam, 5 to 12 percent slopes Sion clay loam, 0 to 5 percent slopes Sion clay loam, 5 to 12 percent slopes Southgate clay loam, 12 to 40 percent slopes Southgate clay loam, 40 to 60 percent slopes Southgate—Rock land complex, 20 to 60 percent slopes Tidal flats Tidal swamp Victory clay loam, 12 to 20 percent slopes Victory clay loam, 20 to 40 percent slopes Volcanic rock land VIRGIN ISLANDS of the UNITED STATES CONVENTIONAL SIGNS WORKS AND STRUCTURES BOUNDARIES Highways and roads Poor motor DRAINAGE Trail ... oe Streams, double-line Highway markers Streams, single-line Perennial Railroads Intermittent Crossable with tillage Single track implements Not crossable with Multiple track implements .. Abandoned Unclassified Canals and ditches Lakes and ponds Perennial RELIEF Escarpments Bedrock Depressions ah +3 Crossable with tillage Pipeline implements Not crossable with tillage Cemetery implements a : Contains water most of DAMS civessneusas the time Well, oil or gas Forest fire or lookout station ... Lighthouse Large Rou », Gyhat ie Su? ge. 4 BOT SS Small ° ° SOIL SURVEY DATA Soil boundary and symbol Chert fragments Clay spot Sand spot Gumbo or scabby spot Soil map constructed by Cartographic Division, Soil Conservation Service, USDA, from 1962 and 1963 aerial photographs. Controlled mosaic sheets 1] through 17 based on Puerto Rican coordinate system, Virgin Island extension, Lambert conformal conic projection. 1940 adjustment, Puerto Rican datum. Controlled mosaic sheets 18 through 32 based on Puerto Rican coordinate system, Puerto Rico, St. Croix zone, Lambert conformal conic projection. 1940 adjustment, Puerto Rican datum. 1 a 3 iset, sheet 22 CARIBBEAN SEs ees 1 SR ARID SEBEL SS ET REG SE ERE HES TST USS SES TGS TTT nee Saat BRST Arey pees ee: oar ALT Bek stand ; & i T i 4 i fr “T [ 64740’ } : . 4 = Green Cay, | : ‘ 64°50 ra 4 i rory : = | eA VF & ‘aisiilamesianiiaieaanigncteeiniiniiainiaiiaieiabdl ] ~ Rd Aowdl olin Nall Zanll = a ») E gre) Ne=" ee | RMT ae SE Seanad eats wo i ai oe gee ES SSE: Christiansted Harbor | INDEX TO MAP SHEETS VIRGIN ISLANDS of the UNITED STATES ST. CROIX ISLAND Scale 1:126720 1 0 1 2 3 4 Miles Cs Le arene! ee Soil asso- ciation Dominant soil series Descalabrado-- Fredensborg--- Fraternidad--- SOIL LIMITATIONS FOR SELECTED USES Limiting soil features 10 to 20 inches to bedrock; 12 to 60 percent slopes; moderate permeabil- ity; moderate shrink-swell potential. 20 to 36 inches to bedrock; 5 to 12 percent slopes; moderately slow per- meability; high to moderate shrink- swell potential. to 14 inches to soft limestone or marl; 5 to 40 percent slopes; moder- ate permeability; moderate shrink- swell potential. 10 to 20 inches to soft limestone or marl; clay surface layer; moderately Slow permeability; high to moderate shrink-swell potential; 2 to 5 per- cent slopes. 10 to 20 inches to soft limestone or marl; moderate permeability; moder- ate shrink-swell potential; 2 to 5 percent slopes. Clay profile; slow permeability; very high shrink-swell potential; 0 to 3 percent slopes. Clay profile; slow permeability; very high shrink-swell potential; 2 to 5 percent slopes; poorly drained. Moderately slow permeability; moderate to high shrink-swell potential: 2 to 5 percent slopes. 10 to 20 inches to bedrock; 12 to 60 percent slopes; moderate te moder- ately rapid permeability; moderate to low shrink-swell potential. to 12 percent slopes; moderate per- meability; moderate shrink-swell potential, 10 to 20 inches to bedrock; 12 to 60 percent slopes; moderate permeabil- ity; moderate shrink-swell potential. 20 to 72 inches to bedrock; 5 to 40 percent slopes; moderate permea- bility; moderate shrink-swell potential. 20 to 60 percent slopes; moderate per- meability; moderate shrink-swel] potential, 20 to 40 percent slopes; moderate per- meability; moderate shrink-swell potential, 30 to 50 percent slopes; moderate per- meability; low shrink-sweil poten- tial. Slow permeability; moderate to high shrink-swell potential; 0 to 2 per- cent slopes. 2 to 5 percent slopes; moderately slow permeability; moderate shrink-swell potential, 0 to 3 percent slopes; moderate permea- bility; moderate shrink-swell poten- tial. Degree of limitation for-- Highway location Severe---- Severe---- Moderate to severe. Moderate-- Moderate-- Severe---- Severe---- Moderate-- Severe---- Moderate-- Severe---- Severe---- Severe---- Severe---- Severe---- Moderate-- Moderate-- Moderate-- Foundations for buildings Severe Severe Moderate to severe, Moderate Moderate Severe Severe Septic tank filter fields Moderate to severe, Moderate Moderate Severe Moderate Severe Severe Severe Severe Sewage lagoons Severe---- Severe---- Severe---- Moderate-- Moderate-- Moderate-- Moderate-- Moderate-- Severe---- Moderate-- Severe---- Severe---- Severe---- Severe---- Severe---- Slight ---- Moderate-- Capability subclass VIs, VIIs IVe Vie, VIIe IIIs IlIse IiIs IVw Ile VIs, VIIs IIle VIs, VIIs Vie VIe, VIlIe VIe VIe Ve ITIc IIe 382-314 O - 70 {In pocket) gThis map is one * a set compiled in 1969 as part of a soil survey by the Soil Conservation Service, United States DepaAment of Agricultumg. 1005 000 FEET ISLANDS of the UNITED STATES SHEET NUMBER 1 213 000 FEET ] VIRGIN ISLANDS of the UNITED STATES NO. Controlled mosaic based on Puerto Rican coordinate system, Virgin Islands extension, Lambert conformal conic projection. 1940 adjustment, Puerto Rican datum. a N (Joins sheet 5) “faa RV ASHER! 1025 000 FEET 200 000 FEET (Joins sheet 2) 1 Mile —=2 5000 Feet 0 1000 2000 3000 4000 5000 15840 Scale 1 Re ee a a Ca eet @) VIRGIN ISLANDS of the UNITED STATES — SHEET NUMBER 2 (Joins lower right) Se 1025000 FEET SS XK = be 213 000 FEET 1028 000 FEET 214 000 FEET 1 Mile 5 000 Feet 213 000 FEET 1030 000 FEET (Joins upper left) 2 (Joins sheet 1) 0 Scale 1:15840 1000 VIRGIN ISLANDS of the UNITED STATES NO. Et a set compile in 1969 as part of a soil survey by the Soil Conserv Service, United States Depgrt of Agriculty 2000 & This map is one 3000 4000 5 000 Lo 000 FEET Controlled mosaic based on Puerto Rican coordinate (Joins sheet 6) system, Virgin Islands extension, Lambert conformal peer ERE conic projection. 1940 adjustment, Puerto Rican datum. , This map is onegof a set compiled in 1969 as part of a soil survey by the Soil Conservation Service, United States De®irtment of Agricultgre. ) VIRGIN ISLANDS of the UNITED STATES NO, VIRGIN 965 000 FEET ISLANDS of the UNITED STATES SHEET NUMBER 3 200 000 FEET INSET B 975 000 FEET 212000 FEET 290 000 FEET 971 000 FEET INSET A (Joins lower left, sheet 3) 187 000 FEET 980 000 FEET 185 000 FEET k= Sa * na ate PX Controlled mosaic based on Puerto Rican coordinate (Joins inset A) system, Virgin Islands extension, Lambert conformal conic projection. 1940 adjustment, Puerto Rican datum. INSET C 974 000 FEET 201 500 FEET 200 500 FEET 977 000 FEET 985 000 FEE (Joins sheet 4) 187 000 FEET —_» 1 Mile 5000 Feet 15840 3000 2000 1000 0 Scale 1: 4000 5000 1 Mile ee 5 000 Feet 4000 3000 2000 1000 5000 Scale 1:15840 VIRGIN ISLANDS of the UNITED STATES — SHEET NUMBER 4 985 000 FEET 200 000 FEET (Joins sheet 3) (Joins sheet 5 ) 187 000 FEET Controlled mosaic based on Puerto Rican coordinate 1005 000 FEET system, Virgin Islands extension, Lambert conformal conic projection. 1940 adjustment, Puerto Rican datum. SIN ISLANDS of the UNITED STATES NO. 4 VIRG This map is one of a set comp in 1969 as part of a soil surve by the Soil Conse Servi Unite State Depa of Agric §This map is one 4 a set compiled in 1969 as part of a soil survey by the Soil Conservation Service, United States Dep#tment of Agricultume. S VIRGIN ISLANDS of the UNITED STATES NO. VIRGIN ISLANDS of the UNITED STATES — SHEET NUMBER 5 1005 000 FEET Joins sheet 1 BS Sa 200 000 FEET (Joins sheet 4) (Joins sheet 6) JuB i w a °o KR Ww: © ss SS : : 4 é : : y A : \ A . 2 E Controlled mosaic based on Puerto Rican coordinate (Joins sheet 1 1) 1025 000 FEET system, Virgin Islands extension, Lambert conformal conic projection. 1940 adjustment, Puerto Rican datum. 1 Mile 5000 Feet 1000 2000 3000 4000 5000 Scale 1:158 SHEET NUMBER 6 the UNITED STATES ISLANDS | of VIRGIN Joins sheet 2) ( + 025 000 FEET ‘agPYINDABY JO JUaWYHEq $ayeIS payuN ‘ad!A1aS UONeMasUOD |!OS ayy Aq Keds |JOS & 40 ed se 6961 YU! Palidwoo jas e yy auO S| dew sul § 9 “ON SALVIS GALINA 24+ $9 SONV ISI NISUIA 1334 000 002 O:=— ¥9a4 000S ys suo) _ Tr x (¢ s20ys sulor) Ov8GT:T ales 0 0001 0002 OOOE 1334 000 281 000 S aIIW I 0 % % Controlled mosaic based on Puerto Rican coordinate (Joins sheet 12) system, Virgin Islands extension, Lambert conformal 1940 adjustment, Puerto Rican datum. conic projection. VIRGIN ISLANDS of the UNITED STATES SHEET NUMBER 7 1045 000 FEET 200000 FEET Si 5000 Feet (Joins sheet 8) 15840 0) Scale 1 4 a 3 2 ~ CJ = ‘o r= § E 5 & a « 3 3 77) oh 2 56 ao nee) fw Oe &§ < = 2” 20 Ss g w = a OD 2 = o Bu es gf 0 bee 2) g. 2 Pe s <q oe oJ 2-2 é 42 Oo a pe panes s 7. 2 a E 8 7 « ) e c ° 2 a s E a = = fas PIELSBURY 187 000 FEET i i 4 ~ — es : ee - 1 065000 FEET Controlled mosaic based on Puerto Rican coordinate (Joins sheet 13) system, Virgin Islands extension, Lambert conformal conic projection. 1940 adjustment, Puerto Rican datum. saangnouBy JO UAW ZeECHQ sajeis payuN ‘ad1AaG UO!}EAIaSUOD |!0S ay) Aq Aaains jjos e jo yued se G9G6T UY! Pajidwod yas e jo y° s| dew siyy 4 8 “ON SSLVLS GALINA 244 $9 SONVISI NIDMIA (6 #9ays sulor) 1334 000 £8 1 085 000 FEET beet Cinnamon Bay — SHEET NUMBER 8 the UNITED STATES ISLANDS _ of VIRGIN (Joins sheet 14) 1940 adjustment, Puerto Rican datum. 1 065 000 FEET 4334 000 002 system, Virgin Islands extension, Lambert conformal Controlled mosaic based on Puerto Rican coordinate conic projection. (Z 49@ys sulor) OvSST:T ales (@) z < 3994 000S (e) ooo lt 000¢ OOO € 000 000S aw 0 % K % I eee () —— 1284 0006 SHEET NUMBER 9 ISLANDS of the UNITED STATES VIRGIN OV8ST:T a1e9S 0) 000 t 0002 o00€ 000% 000S altw 1 0 % 7 % if 41333 000 281 Pm) : 4 Sy 1 105 000 FEET Controlled mosaic based on Puerto Rican coordinate 1 085 000 FEET 1334 000 002 g saays sulor) 6 ‘ON SALVLS GALINN 244 3° SONV TSI NISUIA 4 a “ ainyjnouBy jo juawyeleg S8IBIS PAU ‘ad!MaG UOIJeAaSUOD 10S ayy Aq AansNs |!0S e@ JO yued Se GGGT u! pajidwoo yas e jo auo si dew siyy § (Joins sheet 15) Lambert conformal system, Virgin Islands extension, conic projection. Puerto Rican datum 1940 adjustment, 1 Mile ee ISLANDS | of UNITED STATES SHEET NUMBER 10 200 000 FEET 5000 Feet (Joins sheet 9) 0 2000 1000 ( Scale 1:15840 3000 4000 5000 Controlled mosaic based on Puerto Rican coordinate 187 000 FEET system, Virgin Islands extension, Lambert conformal conic projection. 1940 adjustment, Puerto Rican datum. 1125000 FEET! 10 1969 as part of a soil survey by the Soil Conserv Service, United States De&artm of AgriculPu VIRGIN ISLANDS of the UNITED STATES NO. cA This map is one of a set compil in t & this map is o * of a set compiled in 1969 as part of a soil survey by the Soil Conservation Service, United States Ogpartment of Agricyture: 11 VIRGIN ISLANDS of the UNITED STATES NO, 187 000 FEET i VIRGIN ISLANDS | of Sai, 4 Flamingo Point the UNITED STATES pup BB SEA } E SHEET NUMBER 11 994 000 FEET 175000 FEET 173 000 FEET 998 000 FEET (Joins sheet 12) 174000 FEET Controlled mosaic based on Puerto Rican coordinate system, Virgin Islands extension, Lambert conformal conic projection. 1940 adjustment, Puerto Rican datum. 1025000 FEET 1 Mile 5 000 Feet 1000 2000 3000 Scale 1:158 1 Mile % % 5000 Scale 1:15840 187 000 FEET (Joins sheet 11) CARIBBEAN ISLANDS of the UNITED STATES SHEET NUMBER 12 conic projection. Controlled mosaic based on Puerto Rican coordinate system, Virgin Islands extension, Lambert conformal 1940 adjustment, Puerto Rican datum. (Joins sheet 17) (Joins sheet 1 3) 174 OOO FEET 12 S NO. ED STATE of the UNITE \C BS VIRGIN ISLAND vw F - * This map is one of a set compil in 1969 as part of a soi| survey by the Soil Conserv Service, United States DR ertment of AgricMur gertment of Agriculyre. 13 VIRGIN ISLANDS of the UNITED STATES NO. eof a set compiled in 1969 as part of a soil survey by the Soil Conservation Service, United States De = ¢ This map is on 1045 000 FEET Cua = pea Ww iris = 8 5 oO = (Joins sheet 12) L VIRGIN ISLANDS of the UNITED STATES SHEET NUMBER 13 Controlled mosaic based on Puerto Rican coordinate system, Virgin Islands extension, Lambert conformal conic projection. 1940 adjustment, Puerto Rican datum. (Joins sheet 7) (Joins sheet 14) 174 000 FEET 1065 000 FEET 1 Mile ——= z () 5000 Feet 15840 3000 2000 1000 0 Scale 1: 4000 5000 “e4gn|nolsBy jo juaWyBIeq Sexes pazjUN ‘a2!MVag UONEAASUOD |!0S 343 Aq AoAINS ||OS © JO Wed Se GGT UY) Palidwoo yes & jCyauO sj dew s}yL ? . Pl ‘ON SSLVLS GALINA 244 4° SONVISI NIDUMIA (SL HO0US SWOF: ) 1334 000 vit 1 085 000 FEET ins sheet 8) (Jo SHEET NUMBER 14 n lu < Ee nm Q lw Ee Zz =) © x= ~ = ° 72) fa) 5 2 VIRGIN 1940 adjustment, Puerto Rican datum. system, Virgin Islands extension, Lambert conformal 1 065 000 FEET conic projection. Controlled mosaic based on Puerto Rican coordinate 1334 000 281 = ) (EL yooys suior) (¢) Ovest: T aje9S 924 000S 0001 aIIW 0 I (91 4@ays sulor) 1334 000 PZT 1334 00S €ZT 1 105 000 FEET (Joins lower left) 1100 000 FEET (Joins sheet 9) 1 099 500 FEET (Joins upper right) SHEET NUMBER 15 ”n ul < E n fa) lu = z > a <= - -_— ° ”n ja) 5 = VIRGIN 1940 adjustment, Puerto Rican datum. 1085 000 FEET system, Virgin Islands extension, Lambert conformal Controlled mosaic based on Puerto Rican coordinate conic projection. 1334 000 281 j ~ (vy 42eyYs sulor) St "ON SSLVLS GALINA 244 3° SONV ISI NIOYIA 4 d “@4N}|NIJBY JO JUaWYedEQ $aze1S Pa}|UN ‘Ad|ABS UOIJEAIaSUOD |!OS ay} Aq A@Ains jJos e yO Jed se GOGT Ul Pajidwoo jas e jo auo sj dew siy) 1 Mile % =e) 5 000 Feet 4000 3000 2000 1000 5000 Scale 1:15840 187 000 FEET (Joins sheet 15) 1105000 FEET (Joins sheet 10) | duck Island VIRGIN Controlled mosaic based on Puerto Rican coordinate system, Virgin Islands extension, Lambert conformal conic projection. 1940 adjustment, Puerto Rican datum. ISLANDS | of the UNITED STATES SHEET NUMBER 16 agan Island 1 125 000 FEET “1174 000 FEET ’ 16 VIRGIN ISLANDS of the UNITED STATES NO. C This map is one of a set compil in 1969 as part of a soil survey by the Soil Conser Service United States Départ of Agricul 4 € TW map is one of @set compiled in 1969 as part of a soil survey by the Soil Conservation Service, United States DepartM@ent of Agricultureay Tie VIRGIN ISLANDS of the UNITED STATES NO. mt 1025 000 FEET VIRGIN ISLANDS of the UNITED STATES — SHEET NUMBER 17 174 000 FEET 174 000 FEET CARIBB SEA Controlled mosaic based on Puerto Rican coordinate system, Virgin Islands extension, Lambert conformal conic projection. 1940 adjustment, Puerto Rican datum. INSET A 1047 300 FEET Ww ld [e} o o Nn + Joins sheet 12) 7 ra FP inesl Jt Sid thee wre > Sip MS pert, GHEE fo Po (Joins sheet 13) 171 000 FEET 1 062 000 FEET INSET B 1049 800 FEET 161 000 FEET 1045 000 FEET 1 Mile i 5000 Feet 2 ©) , 2000 1000 0 Scale 1:158 3000 4000 5000 SHEET NUMBER 18 ISLANDS of the UNITED STATES VIRGIN 1030 000 FEET a 1334 000 98 @) z—=—_ nyjnausBy jo qusuitedeg s9}81S paiun faojnues uoljzeAsasuoD |10S a4} Aq AoAins jJ0S e jo yaed se GIGI UY! Pajidwoo jas e ye auO S| dew sy 8lL “ON SALVLS GALINA 244 4° SONVIASI NIDMIA (61 4@0ys sulor) ; 1334 000 €4 svat ~ : OvSST:T ae9S ) 0001 0002 OOOE 000+ 0006 aIIW T 1 050 000 FEET (Joins sheet 24) Controlled mosaic based on Puerto Rican coordinate system, Puerto Rico, St. Croix zone, Lambert conformal 1940 adjustment, Puerto Rican datum. conic projection. 1050 000 FEET 86 000 FEET 19 VIRGIN ISLANDS of the UNITED STATES NO. (Joins sheet 18) Pris map is one ry a set compiled in 1969 as part of a soil survey by the Soil Conservation Service, United States DepG&tment of Agricultgge. Se 7 oe Le ; 2 ¢ PPS me ae Controlled mosaic based on Puerto Rican coordinate system, Puerto Rico, St. Croix zone, Lambert conformal conic projection. 1940 adjustment, Puerto Rican datum. VIRGIN ISLANDS of the UNITED STATES SHEET NUMBER 19 § (Joins sheet 25) ne = ye 1070 000 FEET (Joins sheet 20) 73 000 FEET 1 Mile —»>2 5000 Feet 15840 (e) 4000 3000 2000 1000 Scale 1 5000 SHEET NUMBER 20 ISLANDS of the UNITED STATES VIRGIN Q——— 1070 000 FEET 1334 000 98 4224 000S ‘OJgyno|sBy jO JUuaWgReg sajeis pa}iun fg2\n4aS UOIJeAIaSUOD |1OS ayy Aq Aadsns JOS @ yO ed Se GOGT UY! Pajidwod jas e jO,auo sy dew sjyy pninavsBy 4 yaea % OZ “ON SSALVLS GALINA 244 49 SONV1SI NISYIA (LZ 49@y4s susor) Bs ~ / y ij "(61 4994s sulor) OvV8ST:T ale9S ) 0001 0002 OOOE 000S 1334 000 €2 \ | a POE 9 SW T 0) % K 1 090 000 FEET (Joins sheet 26) Controlled mosaic based on Puerto Rican coordinate system, Puerto Rico, St. Croix zone, Lambert conformal conic projection. 1940 adjustment, Puerto Rican datum. y by the Soil Conservation Service, United States Depar@nent of Agricultud@y VIRGIN ISLANDS of the UNITED STATES NO, 21 x S$ map is one Ofga set compiled in 1969 as part of a soil surve: t VIRGIN + 090 000 FEET 86 000 FEET Joins sheet 20) Controlled mosaic based on Puerto Rican coordinate system, Puerto Rico, St. Croix zone, Lambert conformal conic projection. 1940 adjustment, Puerto Rican datum. ISLANDS of the UNITED STATES C A R T B B EA N CHRISTIANSTED SHEET NUMBER 21 (Joins sh eet 27) 1110000 FEET (Joins sheet 22) 73 000 FEET 1 Mile a 5000 Feet 2 ®) : Scale 1:158 1000 x 3 ro) N * : ° sTH8 Ps f=) iS fo) wo - SHEET NUMBER 22 ISLANDS of the UNITED STATES VIRGIN 1 110 000 FEET 1128 000 FEET “T334 000 98 Q==—— 1994 000S “earginouBy 40 quawisged S2}EIS P2}UP ‘BDIAlaG UOIJENaSUOD |!0S ay} Aq Aansns |jOS e yO ed Se GIGT Ul Palidiuoo jas e 4} s ZZ ‘ON SSALVLS GSLINA 944 19 SONVTISI NIDMIA 1334 000 98 1135 000 FEET 1334 000 88 Oo guo $s - } dew a | (Ez saeys sulor) =< eZ a7 We *) 5 ah) Y 1334 000 €2 \ ait | 1130000 FEET (Joins sheet 28) Controlled mosaic based on Puerto Rican coordinate system, Puerto Rico, St. Croix zone, Lambert conformal conic projection. 1940 adjustment, Puerto Rican datum. ISLANDS of the UNITED STATES One SHEET NUMBER 23 VIRGIN 1130000 FEET ee 4334 000 62 vest: T 9189S 7224 0005S 000 Tt 0002 OOO€ leleleh 4 000s aIIW (e) % K % I 41334 00099 1 150 000 FEET dejatre are Cu 1940 adjustment, Puerto Rican datum. system, Puerto Rico, St. Croix zone, Lambert conformal Controlled mosaic based on Puerto Rican coordinate conic projection. >) : Vast P Fe iz ee resus sues) | (ag 196 €Z “ON SSALVLS GALINA 244 $9 SONVTS! NISXIA -aiffinaysBy jo juawugea S2}BIS Pa}JUN ‘eIjAWaG UO!}EAJasUOD ||OS a4} Aq A@AINS ||OS B@ jO Jed Se GGGT U} palidwoo jas e jo“buo Ss] dew sjyy a 2s Seale) 4 = + “2 we Sa jo} oO wo °o + fee) ite) et ormc:: Lame | 2 oO 5) ” ie} So te} a x fe} So fo} N EB J So oS to} mo to) =HS t+ So [eo] Oo wo . 1 030 000 FEET 73 000 FEET VIRGIN ISLANDS _ of Controlled mosaic based on Puerto Rican coordinate system, Puerto Rico, St. Croix zone, Lambert conformal conic projection. 1940 adjustment, Puerto Rican datum. the UNITED STATES SHEET NUMBER 24 ma a, Ae of, (Joins sheet 18) z RSs (Joins sheet 29) (Joins sheet 25) 1 050 000 FEET 60 000 FEET 24 Soll Conserv Service, United States DMB rment of AgriclMur VIRGIN ISLANDS of the UNITED STATES NO. This map is one of a set compile In 1969 as part of a soil survey by the 6... map is one ® a set compiled in 1969 as part of a soil survey by the Soil Conservation Service, United States Department of Agricul. VIRGIN TSLANDS of i WW WwW uh ° 2 o a) n 1 050 000 FEET Controlied mosaic based on Puerto Rican coordinate = system, Puerto Rico, St. Croix zone, Lambert conformal conic projection. 1940 adjustment, Puerto Rican datum. VIRGIN ISLANDS _ of the UNITED STATES SHEET NUMBER 25 Et en ae o v we oS fo] °o wo ~ oO N _ ® {| o {<= a “ -= ° 4 ~— wo fo} Ove al 4 i] o ” 8 = x So oO oS N ® 8 (a) [=] ado ats) = o s, wo Soe ra 8 3 ° © 10) 1000 Scale 1:15840 2000 3000 4000 5000 VIRGIN ISLANDS of the UNITED STATES — SHEET NUMBER 26 (Joins sheet 20) = 73 000 FEET 52. =e) 2) (Joins sheet 25) (Joins sheet 27) 60 000 FEET id EAB Controlled mosaic based on Puerto Rican coordinate (Joins sheet 3 1) system, Puerto Rico, St. Croix zone, Lambert conformal conic projection. 1940 adjustment, Puerto Rican datum. e° map is one ga set compiled in 1969 as part of a soil survey by the Soil Conservatio Service, United States gees of et ovest” T 2189S | @) — 3324 0005 0001 0002 000€ 000 0005 aw 0 % K % i 1110000 FEET (Joins sheet 21) (Joins sheet 32) SHEET NUMBER 27 ISLANDS of the UNITED STATES VIRGIN 1940 adjustment, Puerto Rican datum. system, Puerto Rico, St. Croix zone, Lambert conformal Controlled mosaic based on Puerto Rican coordinate conic projection. 1 090 000 FEET PITS 4334 000 €2 (9Z 420Ys sulof ZZ ‘ON SALVILS GALINA 24+ 3° SONVISI NIDYIA ‘aunyjnauBy jo jUaWIedag SajeIS PAU ‘ad\AIaS UOI}EAaSUOD |10S ay} Aq AaAsNS JOS e jo Jued Se GOGI UY! pajidiuod jas e& jo auo Si dew siy) & 2 ™, é SHEET NUMBER 28 ISLANDS of the UNITED STATES VIRGIN (Joins sheet 22) 1110000 FEET 41334 000 €2 @) z= 1994 000S aIIWT © ‘'’ 1 ‘aunqjMouBy yo yuawyedag sajejg paylus) ‘8D1NIaG UO!}eAIAaSUOD |!0S ay} Aq AaAINS |1OS e yO j4ed Se GOGT U! pajidwoo jas e jo w s} dew siut . 8Z "ON SALVLS GALINA 244 3° SONVISI NIOMIA us Swe > i (ZZ 490Ys sulor) Ovss 13: T 8189S celelon 0002 OOOE celelehs 000S 0 % % % I (€Z #90Ys sulor 1334 000 09 & ae 1 130 000 FEET Controlled mosaic based on Puerto Rican coordinate (Joins inset, sheet 32) system, Puerto Rico, St. Croix zone, Lambert conformal 1940 adjustment, Puerto Rican datum. conic projection. i ~ a ment of Agricult UR. a @ia set compiled in 1969 as part of a soil survey by the Soil Conservation Service, United States Dep: Tris map is one 29 VIRGIN ISLANDS of the UNITED STATES NO. 60 000 FEET 1030 000 FEET r (Joins sheet 29, lower right) 1032 000 FEET = G 47 000 FEET Sandy Point Controlled mosaic based on Puerto Rican coordinate system, Puerto Rico, St. Croix zone, Lambert conformal conic projection. 1940 adjustment, Puerto Rican datum. (Joins inset, up a'r: per left) 45000 FEET VIRGIN ISLANDS of the UNITED STATES Pits PDAS SHEET NUMBER 29 tf HM MED Whe Ch af i yy Ay, a” Lat Joins sheet 24 ) Pak aa ‘tin “4s ch: 1 050 000 FEET 47 000 FEET (Joins sheet 30) 1 Mile 5000 Feet 1000 2000 4000 3000 5000 Scale 1:15 1 Mile % 5 000 Feet 4000 3000 2000 1000 5000 ae) Scale 1:15840 VIRGIN ISLANDS of the UNITED STATES — SHEET NUMBER 30 1.050 000 FEET (Joins sheet 25) 60 00O FEET (Joins sheet 29) (Joins sheet 31) 47 000 FEET Controlled mosaic based on Puerto Rican coordinate 1070000 FEET | system, Puerto Rico, St. Croix zone, Lambert conformal conic projection. 1940 adjustment, Puerto Rican datum. 30 D STATES NO. IN ISLANDS of the UNITE o) VIR( Ament of Agricutge Cris map is ene; a set compiled in 1969 as part of a soil survey by the Soil Conservat Service, United States Dep « + Agyculre. é Gris map imorteps a set compiled in 1969 as part of a soil survey by the Soil Conservation Service, United States vewgffiment VIRGIN ISLANDS of the UNITED STATES NO. 31 60 000 FEET = So ~ _ ® o < a wo = oO}. [\zg 1070 000 FEET * Be VIRGIN Controlled mosaic based on Puerto Rican coordinate system, Puerto Rico, St. Croix zone, Lambert conformal conic projection. 1940 adjustment, Puerto Rican datum. ?.- ae, a= te —- ISLANDS of the UNITED STATES SHEET NUMBER 31 1 090 000 FEET 47 000 FEET 5000 Feet 4000 3000 2000 1000 5000 Scale 1:158 VIRGIN ISLANDS of the UNITED STATES — SHEET NUMBER 32 1090 000 FEET (Joins sheet 27) _ 60 OOO FEET (lower left) en @ = 3 ane o (re Q fo} 3 wo ¢ ¢ *s % r= £ f a 3 5 N @ a 7 = @ 5 (Joins sheet 28) 2 ¢ n 2 1110000 FEET ra & = Ee @ £ it qd oc« 2 < . 8 ty eae 2 ° irs a 3 bo Q Ww 3 or 8 Ee ee — 1S Z 3B ms) 5 73 . wir fs a 5 1113 000 FEET re a fo) = 4 3 & 2 no a ‘oO Qe. 2 oOo on 2 Zz 8 a _ x a © - 3 oO =_— = oO Zz a a , ae ro) 2 ae 8 S12 fo} c = s 3 x a S 8 3 oO ° 8 ¥ ° #2 a = x SE 2 oO E 3 d ts) o HS TAS Cc A R I B B E A N S E A fo} iS fo} wo FS - Wu ray wu fey 3 fo) iS t+ Controlled mosaic based on Puerto Rican coordinate 1110 000 FEET system, Puerto Rico, St. Croix zone, Lambert conformal conic projection. 1940 adjustment, Puerto Rican datum.