• TABLE OF CONTENTS
HIDE
 Front Cover
 How to use this soil survey
 Table of Contents
 Introduction
 How this survey was made
 General soil map
 Descriptions of the soils
 Use of the soils for crops and...
 Use of the soils for shade and...
 Use of the soils for range
 Use of the soils for woodland
 Use of the soils in engineerin...
 Use of the soils for recreational...
 Formation and classification of...
 Additional facts about the...
 Literature cited
 Glossary
 Guide to mapping units
 Index to map sheets
 Map






Title: Soil survey, Virgin Islands of the United States
CITATION PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00027418/00001
 Material Information
Title: Soil survey, Virgin Islands of the United States
Physical Description: 78 p. : illus., fold. col. maps (1 in pocket) ; 28 cm.
Language: English
Creator: United States -- Soil Conservation Service
Rivera, Luis H
Publisher: For sale by the Supt. of Docs., U.S. Govt. Print. Off.
Place of Publication: Washington
Publication Date: 1970
 Subjects
Subject: Soil surveys -- Virgin Islands of the United States   ( lcsh )
Genre: bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Bibliography: p. 76.
Statement of Responsibility: by Luis H. Rivera and others.
General Note: Cover title.
Funding: U.S. Department of Agriculture Soil Surveys
 Record Information
Bibliographic ID: UF00027418
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: Government Documents Department, George A. Smathers Libraries, University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 000485295
oclc - 00124976
notis - ACQ3218
lccn - 75610116

Table of Contents
    Front Cover
        Cover
    How to use this soil survey
        Page i
    Table of Contents
        Page ii
    Introduction
        Page 1
    How this survey was made
        Page 2
    General soil map
        Page 3
        Descalabrado-Jacana association
            Page 3
        Aguilita-Fredensborg-Sion association
            Page 3
        Fraternidad-Aguirre-Glynn association
            Page 3
        Southgate-Parasol association
            Page 4
        Cramer-Isaac association
            Page 4
        Dorothea-Victory-Magens association
            Page 4
        Cornhill-Coamo-San Anton association
            Page 5
    Descriptions of the soils
        Page 6
        Aguilita series
            Page 6
            Page 7
        Aguirre series
            Page 8
        Coamo series
            Page 9
        Cobbly alluvial land
            Page 10
        Cornhill series
            Page 10
        Cramer series
            Page 11
            Page 12
        Descalabrado series
            Page 13
        Diamond series
            Page 14
        Dorothea series
            Page 15
        Fraternidad series
            Page 16
        Fredensborg series
            Page 17
        Glynn series
            Page 18
        Hesselberg series
            Page 19
        Isaac series
            Page 20
        Jacana series
            Page 21
        Jaucas series
            Page 22
        Lavallee series
            Page 23
        Leveled clayey series
            Page 24
        Leveled marly series
            Page 24
        Leveled rocky series
            Page 24
        Limestone rock land
            Page 24
        Made land
            Page 24
        Magens series
            Page 24
        Parasol series
            Page 25
        Pozo blanco series
            Page 26
        San Anton series
            Page 27
        Sion series
            Page 28
            Plate 1
            Plate 2
        Southgate series
            Page 29
        Tidal flats
            Page 30
        Tidal swamps
            Page 30
        Victory series
            Page 30
        Volcanic rock land
            Page 31
    Use of the soils for crops and pasture
        Page 32
        Capability grouping
            Page 32
            Page 33
            Page 34
            Page 35
            Page 36
        Estimated yields
            Page 37
            Page 38
    Use of the soils for shade and fruit trees, shrubs, and ornamentals
        Page 39
    Use of the soils for range
        Page 39
        Range sites and condition classes
            Page 39
        Descriptions of range sites
            Page 39
            Page 40
            Page 41
            Page 42
            Page 43
            Page 44
    Use of the soils for woodland
        Page 45
        Woodland suitability groups
            Page 45
            Page 46
    Use of the soils in engineering
        Page 47
        Engineering classifications
            Page 47
        Estimated properties of the soils
            Page 47
        Interpretations of engineering properties
            Page 47
            Page 48
            Page 49
            Page 50
            Page 51
            Page 52
            Page 53
            Page 54
            Page 55
            Page 56
            Page 57
            Page 58
            Page 59
            Page 60
        Engineering test data for soils
            Page 61
            Page 62
            Page 63
    Use of the soils for recreational development
        Page 64
        Page 65
        Page 66
        Page 67
        Page 68
    Formation and classification of the soils
        Page 69
        Factors of soil formation
            Page 69
            Plants and animals
                Page 69
            Climate
                Page 69
            Parent material
                Page 70
            Relief
                Page 70
            Age of landorm
                Page 70
        Representative soil horizons
            Page 70
        Classification of the soils
            Page 71
            Page 72
    Additional facts about the islands
        Page 73
        Climate
            Page 73
            Page 74
        Water supply
            Page 75
        Natural vegetation
            Page 75
    Literature cited
        Page 76
    Glossary
        Page 77
        Page 78
    Guide to mapping units
        Page 79
        Page 80
    Index to map sheets
        Page 81
        Page 82
        Page 83
    Map
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
        Page 22
        Page 23
        Page 24
        Page 25
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
Full Text
PkMT 77 c,., r, -%77777


IT \~ 6~


SOIL SURVEY

VIRGIN ISLANDS
of the United States


AL


UNITED STATES DEPARTMENT AGRICULTURE
Soil Conservation Service


Issued August 1970





























HOW TO USE THIS SOIL SURVEY


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-


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 to
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 broad
patterns of soils are described. They may also be
interested in the section "Additional Facts About
the Islands."


Major fieldwork for this soil survey was done in the period 1964-65.
Soil names and descriptions were approved in 1965. Unless otherwise in-
dicated, statements in the publication refer to conditions on the islands
in 1965. This survey was made by the Soil Conservation Service. It is
part of the technical assistance furnished to the Virgin Islands Soil
Conservation District.
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, Washington, D. C. 20250.


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


OW THIS SURVEY WAS MADE---------------------

"NERAL SOIL MAP------------------------------
1. Descalabrado-Jacana Association--------
S2. Aguilita-Fredensborg-Sion Association--
3. Fraternidad-Aguirre-Glynn Association--
4. Southgate-Parasol Association----------
5. Cramer-Isaac Association---------------
6. Dorothea-Victory-Magens Association----
7. Cornhill-Coamo-San Anton Association---

DESCRIPTIONS OF THE SOILS---------------------
Aguilita Series----------------------------
Aguirre Series-----------------------------
Coamo Series-------------------------------
Cobbly Alluvial Land-----------------------
Cornhill Series----------------------------
Cramer Series------------------------------
Descalabrado Series------------------------
Diamond Series-----------------------------
Dorothea Series----------------------------
Fraternidad Series-------------------------
Fredensborg Series-------------------------
Glynn Series-------------------------------
Hesselberg Series--------------------------
Isaac Series-------------------------------
Jacana Series------------------------------
Jaucas Series------------------------------
Lavallee Series----------------------------
Leveled Clayey Land------------------------
Leveled Marly Land-------------------------
Leveled Rocky Land-------------------------
Limestone Rock Land------------------------
Made Land----------------------------------
Magens Series------------------------------
Parasol Series-----------------------------
Pozo Blanco Series-------------------------
San Anton Series---------------------------
Sion Series--------------------------------
Southgate Series---------------------------
Tidal Flats--------------------------------
Tidal Swamps------------------------------
Victory Series-----------------------------
Volcanic Rock Land-------------------------


2 USE OF THE SOILS FOR CROPS AND PASTURE--------
Capability Grouping------------------------
3 Estimated Yields---------------------------
3
3 USE OF THE SOILS FOR SHADE AND FRUIT TREES,
3 SHRUBS, AND ORNAMENTALS-----------------
4
4 USE OF THE SOILS FOR RANGE--------------------
4 Range Sites and Condition Classes----------
5 Descriptions of Range Sites----------------

6 USE OF THE SOILS FOR WOODLAND-----------------
6 Woodland Suitability Groups----------------
8
9 USE OF THE SOILS IN ENGINEERING---------------
.0 Engineering Classifications----------------
.0 Estimated Properties of the Soils----------
1 Interpretations of Engineering Properties--
3 Engineering Test Data for Soils------------


Page

32
32
37


39

39
39
39

45
45

47
47
47
47
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-------------- --------------- 76

GLOSSARY- -------------------------------- 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
loam 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
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
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








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
loam 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
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
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








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
loam 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
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
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








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
loam 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
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
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. They are strong-
ly sloping, moderately deep, and well drained. They
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.


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








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. They are strong-
ly sloping, moderately deep, and well drained. They
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.


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








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. They are strong-
ly sloping, moderately deep, and well drained. They
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.


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 780 and
800 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 gravelly clay
loam, 20 to 40 percent slopes, in a brushy area on
St. Croix, half a mile north and 125 feet west of
an intersection 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.
AC--6 to 10 inches, mixed very dark grayish-brown
(10YR 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.
C--10 to 60 inches +, white (10YR 8/1) soft lime-
stone or marl; few to common hard limestone
concretions.

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 knolls 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








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 780 and
800 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 gravelly clay
loam, 20 to 40 percent slopes, in a brushy area on
St. Croix, half a mile north and 125 feet west of
an intersection 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.
AC--6 to 10 inches, mixed very dark grayish-brown
(10YR 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.
C--10 to 60 inches +, white (10YR 8/1) soft lime-
stone or marl; few to common hard limestone
concretions.

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 knolls 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 Area Extent Soil Area Extent


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
slopes---------------------------
Coamo clay loam, 2 to 5 percent
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,
eroded---------------------------
Dorothea clay loam, 20 to 40 per-
cent slopes----------------------
Dorothea clay loam, 40 to 60 per-
cent 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-------------------


Acres


632

2,086

2,052

2,101

388

761

2,161
96

1,336

250

10,921

11,838

1,869

4,154

2,035

1,156

4,082

8,244

1,265


91

962

591

2,549

585

264

2,229

414

929

167


Percent


0.7

2.4

2.4

2.5

.5

.9

2.5
.1

1.6

.3

12.8

13.7

2.2

4.9

2.4

1.4

4.8

9.7

1.5


.1

1.1

.7

3.0

.7

.3

2.6

.5

1.1

.2


Hesselberg clay, 0 to 2 percent
slopes--------------------------
Isaac clay loam, saprolitic sub-
stratum, 12 to 20 percent slopes,
eroded--------------------------
Isaac clay loam, saprolitic sub-
stratum, 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 per-
cent 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 per-
cent slopes---------------------
Sion clay loam, 0 to 5 percent
slopes---------------------------
Sion clay loam, 5 to 12 percent
slopes--------------------------
Southgate clay loam, 12 to 40 per-
cent slopes---------------------
Southgate clay loam, 40 to 60 per-
cent 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----------------
Mines and pits---------------
Total---------------------


Acres


540


168


525

735

193

1,663

86

1,387

227
28
307
84
167
225

177

96

429

174

98

3,713

741

2,221

488

385

792

399
407
996

138

389
1,185
12
85,383


Percent


0.6


.2


.6

.7

.2

1.9

.1

1.6

.3
(1/)
.4
.1
.2
.3

.2

.1

.5

.2

.1

4.3

.9

2.6

.6

.5

.9

.5
.5
1.2

.2

.5
1.4
(1/)
100.0


1Less than 0.05 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 coastal 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 780 and
800 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.
Drainage 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, very 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.
A12--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.
A13--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 (SY 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.
C1--36 to 45 inches, olive-gray (5Y 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, 5Y 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 (5Y 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 780 and 800F.
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 thic .
IIClca--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 boundary. 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, medium,
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


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 800 F.
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;








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, medium,
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


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 800 F.
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 780
and 800 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.

A1--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.
B1--9 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 5 inches thick.
B2t--13 to 19 inches, dark reddish-brown (2.5YR
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.
R--19 inches +, greenish-gray, hard-bedded vol-
canic mudstone (very difficult to dig with
spade); red and dark reddish-brown stains
along fracture planes.

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









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 15 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)


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 780 and 800 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 road:

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.
B1--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.
B2--10 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
5 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.

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.








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


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 780
and 800 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 (DlB).--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 (D1C2).--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 780 and 800 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


of Lilliendahl junction, which is 1,000 yards east
of the Dorothea Experiment Station and 75 feet
south of the road:

A1--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--ll 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


382-314 O 70 2








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 5, 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 780 and 800 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-


ture; friable, sticky, plastic; common
roots; strongly effervescent; clear, smooth
boundary.
A1--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-
Ssides 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 (5Y 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 600 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 780
and 800 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








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


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 800 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, firm,
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 5YR 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 800 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 (5YR 3/3)
clay; moderate, medium, subangular blocky








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.
B1--7 to 12 inches, dark reddish-brown (5YR 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.
B2--12 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.
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 5YR 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 5YR 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-l;
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


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 780 and 800 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.
B1--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. 3 to
6 inches thick.
B2t--ll 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.
B3--19 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.


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-l; 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 frqm 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 780
and 800 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;








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.
B3--17 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 11
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.

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


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 11
inches thick. The depth to partly weathered volcan-
ic rock is 18 to 28 inches.
This soil is suited to pasture 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, 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)

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 780 and 800 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.
C1--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.
C2--16 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.

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 780 and 800 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








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


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 780 and 800 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-
iegated 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








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


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 780 and 800 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-
iegated 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








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


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 780 and 800 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-
iegated 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








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


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 780 and 800 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-
iegated 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








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


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 780 and 800 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-
iegated 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








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


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 780 and 800 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-
iegated 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. Only a few
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:

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.
A12--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 800 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








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.
C1--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 loam
(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
(10YR 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


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 IIe-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 780 and 800 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 bl-ocky
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. The depth to soft limestone
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)

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 780 and 800 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:








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.
C1--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.
IIC2--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 10YR 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.


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 780 and 800 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;







































-rotlle or Agullita gravelly clay loam.


Profile of Cramer gravelly clay loam.


Rock terraces on Dorothea clay loam, 20 to 40 percent slopes.


Plate I


Descalabrado clay loam, 20 to 40 percent slopes.











Plate II


kw,~P~ -j


Sugarcane on Fredensborg clay, 2 to 5 percent slopes.
Steep wooded area in background is Aguilita gravelly
clay loam, 20 to 40 percent slopes.


Honduras mahogany underplanted in heavy brush.
The soil is Fredensborg clay, 2 to 5 percent slopes.


Farm pond under construction in Dorothea clay loam, 20 to 40
percent slopes. Slope reduces potential storage capacity.


Jaucas sand.








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-l; woodland
group 2; Shallow range site 6, precipitation zone
35 to 45 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,


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 780 and 800 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.


382-314 0- 70 3








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 complex, 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


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 780 and 800 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








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 complex, 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


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 780 and 800 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








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 complex, 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


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 780 and 800 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 5/8). 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
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.
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)








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 IIe-2, IIs-1,
IIc-1, IIIs-1, IIIs-2, IIIsc-l, 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.


Class 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,
IIe. 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, drought, 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-l.
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
are 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.
CAPABILITY 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-1. Thus,
in one symbol, the Roman numeral designates the ca-
pability class, or degree of limitation; the small








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 IIe-2, IIs-1,
IIc-1, IIIs-1, IIIs-2, IIIsc-l, 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.


Class 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,
IIe. 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, drought, 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-l.
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
are 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.
CAPABILITY 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-1. 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 IIe-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,








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


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 because
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








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.


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. Graz-
ing should be controlled and deferred to allow
grasses to reseed. Droughtiness is a limitation.
Irrigation should not be considered.


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. The erosion hazard is very severe unless the
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.


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--

1. Complete fertilization according to the re-
sults of soil tests.
2. Adequate seedbed preparation.
3. Drainage and water control if needed.
4. Planting of proven varieties.
5. 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.

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: 20 tons per acre, green weight,
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): 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.










TABLE 2.--ESTIMATED AVERAGE YIELDS PER ACRE OF PRINCIPAL CROPS UNDER TWO LEVELS OF MANAGEMENT


[Figures in columns A indicate yields under average management; figures
yields under improved management]


in columns B indicate


Sorghum
Tomatoes Sweetpotatoes Grain sorghum for silage Guineagrass
Soil
A B A B A B A B A B

Lb. Lb. Lb. Lb. Lb. Lb. Tons Tons Tons Tons

Aguilita gravelly clay loam, 2 to 5 percent slopes-------- 6,000 7,500 ----- ------ 3,500 4,500 15 18 7 9
Aguirre clay, 0 to 2 percent slopes---------------------- 6,000 7,500 ----- ------ 4,000 5,000 17 20 8 10
Coamo clay loam, 2 to 5 percent slopes-------------------- 7,000 8,500 7,000 9,000 4,000 5,000 19 22 9 11
Cornhill gravelly clay loam, 0 to 2 percent slopes-------- 5,500 7,000 6,500 8,500 3,500 4,500 18 21 8 10
Fraternidad clay, 0 to 3 percent slopes------------------- 6,500 8,000 ----- ------ 4,000 5,000 17 20 8 10
Fraternidad clay, 3 to 12 percent slopes, eroded--------- 5,500 7,000 ----- ----- 3,500 4,500 14 17 6 8
Fredensborg clay, 0 to 2 percent slopes------------------- 7,500 9,000 8,000 10,000 5,000 6,000 22 25 12 14
Fredensborg clay, 2 to 5 percent slopes------------------- 7,000 8,500 7,000 9,000 4,300 5,300 20 23 10 12
Fredensborg clay, 5 to 12 percent slopes, eroded-------- 6,500 8,000 6,000 8,000 4,000 5,000 15 18 7 9
Glynn clay loam, 2 to 5 percent slopes-------------------- 8,000 9,500 8,000 10,000 5,000 6,000 22 25 12 14
Glynn clay loam, 5 to 12 percent slopes, eroded------- 6,500 8,000 7,000 9,000 4,300 5,300 20 23 9 11
Hesselberg clay, 0 to 2 percent slopes-------------------- 6,500 8,000 6,500 8,500 4,000 5,000 17 20 9 11
Jacana clay loam, 2 to 5 percent slopes------------------- 5,000 6,500 ----- ----- 3,500 4,500 14 17 6 8
Jacana clay loam, 5 to 12 percent slopes------------------ 5,000 6,500 ----- ------ 3,500 4,500 14 17 6 8
Lavallee gravelly clay loam, 2 to 5 percent slopes-------- 8,000 9,500 8,000 10,000 5,000 6,000 22 25 12 14
Parasol clay loam, 2 to 5 percent slopes------------------ 8,000 9,500 8,000 10,000 5,000 6,000 22 25 12 14
Parasol clay loam, 5 to 12 percent slopes----------------- 6,500 8,000 7,000 9,000 4,300 5,300 20 23 9 11
Pozo Blanco clay loam, 5 to 12 percent slopes------------- 6,000 7,500 ----- ------ 3,500 4,500 15 18 7 9
San Anton clay loam, 0 to 3 percent slopes---------------- 8,000 9,500 8,000 10,000 5,000 6,000 22 25 12 14
San Anton clay loam, 5 to 12 percent slopes--------------- 6,500 8,000 7,000 9,000 4,300 5,300 20 23 9 11
Sion clay loam, 0 to 5 percent slopes--------------------- 6,500 8,000 6,500 8,500 4,000 5,000 17 20 9 11
Sion clay loam, 5 to 12 percent slopes-------------------- 6,000 7,500 ----- ------ 3,500 4,500 15 18 7 9









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 ORNAMENTALS2


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.


Many of these plants are well suited. Some can
be established under special management. Others,
particularly ornamentals, can be established in
holes, trenches, and garden beds that are filled
with suitable soil material.


USE OF THE SOILS FOR RANGE


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.


By Richard M. Bond and Axel Fredericksen, Agri-
cultural Research Service, Agricultural Experiment
Station, Kingshill, St. Croix.


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
(45 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 overgrazed, these grasses are re-
placed by hurricanegrass and Barbados sourgrass.
Brush invades as range condition becomes poorer.









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 ORNAMENTALS2


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.


Many of these plants are well suited. Some can
be established under special management. Others,
particularly ornamentals, can be established in
holes, trenches, and garden beds that are filled
with suitable soil material.


USE OF THE SOILS FOR RANGE


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.


By Richard M. Bond and Axel Fredericksen, Agri-
cultural Research Service, Agricultural Experiment
Station, Kingshill, St. Croix.


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
(45 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 overgrazed, these grasses are re-
placed by hurricanegrass and Barbados sourgrass.
Brush invades as range condition becomes poorer.









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 ORNAMENTALS2


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.


Many of these plants are well suited. Some can
be established under special management. Others,
particularly ornamentals, can be established in
holes, trenches, and garden beds that are filled
with suitable soil material.


USE OF THE SOILS FOR RANGE


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.


By Richard M. Bond and Axel Fredericksen, Agri-
cultural Research Service, Agricultural Experiment
Station, Kingshill, St. Croix.


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
(45 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 overgrazed, these grasses are re-
placed by hurricanegrass and Barbados sourgrass.
Brush invades as range condition becomes poorer.









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 ORNAMENTALS2


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.


Many of these plants are well suited. Some can
be established under special management. Others,
particularly ornamentals, can be established in
holes, trenches, and garden beds that are filled
with suitable soil material.


USE OF THE SOILS FOR RANGE


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.


By Richard M. Bond and Axel Fredericksen, Agri-
cultural Research Service, Agricultural Experiment
Station, Kingshill, St. Croix.


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
(45 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 overgrazed, these grasses are re-
placed by hurricanegrass and Barbados sourgrass.
Brush invades as range condition becomes poorer.









TABLE 3.--SUITABILITY OF FRUIT TREES, SHADE TREES, EXOTICS, AND ORNAMENTALS
FOR SPECIFIED SOILS ON ST. CROIX

[Figure 1 indicates that the plant is suited to the soil; figure 2 indicates that it is suited under
special management; figure 3 indicates that the plant is not suited]


Soils



00 C
0 0g
0

-4 Co 0o 4 r

Plants J o 1 2 1 1 0 1 r
S- U U Co > 0 -
> 0 > U O '- > U cd
S>- c 0 0 U c 0 0-4 >

Av o cad t 2 2 2 3 3 1 3 2 1 3 4 3 1 U 1 2 c2

Bvo ado--3 2O c2 0 3 2 3 3 3 3 2 l 2 3 2 3 2'

oU cou 2 2 I 41 1 0 2 1 C I 1 1 3 1 1 >-, 4 1
cC 2 1 1 1 3,0 2 2 2 )3 41 1 3 1 1 2 1
4J> 4) U .-4 'U fi U 0 b O )0- 4l-' C- cO >


Croton U U U U W 3 2 1 2 0 ) -1 I
African tulip----------------------- 3 2 2 2 2 2 2 3 2 2 2 3 2 1 3 2 3 2 1 2 2 2
Alamanda----------------------------- 3 2 1 1 1 1 1 3 2 2 2 3 2 1 2 1 3 1 1 2 2
Almond--- ---------------------------- 2 2 2 1 1 3 2 2 2 1 1 1 1 3 1 1 1 1
Australian pine---------------------- 2 2 1 1 1 1 1 2 2 1 1 2 1 1 2 1 1 1 1 1 1
Avocado------------------------------ 2 3 2 2 2 2 3 3 1 3 3 2 1 1 3 1 1 2 2
Bamboo------------------------------ 2 2 2 2 2 2 1 32 2 2 32 2 23 1 1 1 2
Banana, plantain---------------------- 2 2 1 2 1 1 -2 3 _1 2 -L- J _1 1 1
Bougainvillea------------------------ 2 1 1 1 1 1 2 1 1 2 2 1 1 1 3 1 1 1 1
Breadfruit---------------------------- 3 3 3 3 2 2 2 3 2 3 3 3 3 2 3 2 3 2 2 3 2
Cashew------------------------------- 3 2 1 2 1 2 1 3 2 2 2 3 1 1 3 1 2 2 1
Cedar (tabebuia)----------------------1 2 2 2 1 1 1 2 2 1 2 2 1 1 2 1 2 1 1 1 1 1
Coconut palm-------------------------- 2 2 2 2 1 1 1 3 2 1 2 2 1 1 1 1 3 1 1 1 1 1
Cocoplumt---------------------------- 3 3 1 3 2 3 2 3 2 2 2 3 2 1 1 1 3 1 1 2 2 2
Croton-------------------------------- 2 2 1 1 1 1 1 3 2 2 2 3 2 1 2 1 3 1 1 1 2 1
Custardpple-------------------------- 3 3 3 3 2 2 2 2 3 3 3 2 1 3 2 3 2 1 2 2 2
- -------------2 2 2 2 32223 2 1 2 1 3 1 1 2 2 2
Flamboyantree------------------------ 1 2 1 1 1 1 1 2 1 2 1 2 1 1 2 1 3 1 1 1 1 1
Frangipani-------- -- ---------- 1 2 1 1 1 1 2 2 1 1 2 1 1 2 1 3 1 1 1 1 1
Genip-------------------------------- 2 2 1 2 1 1 1 2 2 1 1 2 1 1 2 1 3 1 1 1 1 1
Ginger Thomas------------------------- 1 2 1 1 1 1 1 2 2 1 2 2 1 1 2 1 2 1 1 1 1 1
Gooseberry--------------------------- -2 2 1 2 1 1 1 3 1 1 1 2 2 1 2 1 3 1 1 1 1 1
Governorsplu------------------------2 2 2 2 1 1 1 3 2 1 2 3 2 1 3 1 3 1 1 1 2 1
Guava-------------------------------- 2 2 1 2 1 1 1 2 1 2 1 2 1 1 2 1 2 1 1 2 1 1
Guavaberrytree------------------------ 3 2 2 2 1 1 1 3 3 3 2 3 2 1 3 1 3 1 2 2 3 1
Hibiscus------------------------------ 2 2 2 2 1 1 1 3 2 1 2 2 1 1 2 1 3 1 1 2 2 1
Hogplum ------------------------------ 3 2 1 2 1 1 1 3 1 1 1 2 1 1 3 1 3 1 1 1 1 1
Jerusalemthorn------------------------ 3 3 1 1 2 2 2 3 2 2 1 2 2 2 3 2 3 2 2 2 2 2
Jujube-------------------------------- 2 2 1 1 1 1 1 2 1 1 1 2 1 1 1 1 3 1 1 1 1 1
Lime---------------------------------- 1 2 1 1 1 1 1 2 2 1 2 2 2 1 3 1 2 1 1 1 1 1
Mahogany----------------------------- 1 2 1 1 1 1 1 2 1 1 1 2 1 1 2 1 2 1 1 1 1 1
Maney-------------------------------- 2 2 1 1 1 1 1 3 1 1 1 3 1 1 2 1 3 1 1 1 1 1
Mango--------------------------------- 3 2 1 2 1 1 1 3 2 2 2 3 1 1 3 2 3 1 1 3 2 1
Mesple-------------------------------- 1 2 1 2 1 1 1 2 1 1 2 2 1 1 2 1 1 1 1 1 1 1
Oleander------------------------------ 2 2 1 2 1 1 1 2 1 1 1 3 1 1 2 1 3 1 1 1 1 1
Orange, grapefruit-------------------- 3 3 2 2 2 2 2 3 3 2 2 3 2 2 3 2 3 2 3 2 3 2
Ota Haiti----------------------------- 3 1 1 3 2 2 2 3 2 2 2 3 1 1 1 1 3 1 1 2 1 2
Papaya-------------------------------- 2 2 1 2 1 2 1 3 2 1 2 2 1 1 2 1 3 1 1 1 1 1
Pineapple--- -------------------------- 3 3 1 3 1 1 1 3 3 2 2 3 2 2 3 2 3 1 2 2 3 2
Pomegranate-------------------------- 3 2 2 2 1 1 1 3 3 2 2 3 2 1 3 2 3 1 1 2 2 2
Plums de Terre------------------------ 3 3 2 3 1 1 1 3 2 2 2 3 2 1 3 1 3 1 1 2 2 1









TABLE 3.--SUITABILITY OF FRUIT TREES, SHADE TREES, EXOTICS, AND ORNAMENTALS
FOR SPECIFIED SOILS ON ST. CROIX--CONTINUED


Soils


Plants


Royal palm--------------------------- 3 2 1 3 1 1 1 3 2 1 1 3 2 1 2 1 3 1 1 2 1 1
Seagrape------------------------------ 2 3 2 2 2 2 2 3 2 2 2 2 2 1 1 2 3 1 1 2 2 2
Soursop------------------------------- 2 3 1 3 1 1 1 3 2 2 2 3 2 1 3 2 3 1 1 2 2 1
Sugarapple---------------------------- 2 2 1 1 1 1 1 3 2 2 2 3 1 1 3 1 3 1 1 1 2 1
Tamarind------------------------------ 1 2 1 1 1 1 1 2 1 1 1 2 1 1 2 1 3 1 1 1 1 1
Tanya--------------------------------- 2 3 2 2 2 2 2 3 2 2 2 3 3 1 3 1 3 1 1 1 2 2
Teak---------------------------------- 3 2 2 3 3 3 3 2 1 1 1 2 1 3 1 3 1 1 1 3 1
Turpentine-myrtle--------------------- 1 2 1 2 1 1 1 2 1 1 1 2 1 1 2 1 3 1 1 1 1 1
West Indian cherry-------------------- 2 2 1 2 1 1 1 3 2 1 1 3 1 1 3 1 3 1 1 1 1 1
Yam----------------------------------- 3 3 2 2 2 3 2 3 2 1 3 3 2 1 2 1 3 1 2 1 1 1


. l l lI I I lI l








TABLE 4.--SUITABILITY OF FRUIT TREES, SHADE TREES, EXOTICS, AND ORNAMENTALS FOR SPECIFIED
SOILS ON ST. THOMAS AND ST. JOHN

[Figure 1 indicates that the plant is suited to the soil; figure 2 indicates that it is suited under
special management; figure 3 indicates that the plant is not suited]

Soils



0 0
O Co C a

S3 1 1 1 1 2 2 3 1 0 1












Australian pine-. ---.... ---.............. 2 1 1 1 1 1 1 1 2 1 2 1 1 1d 1 1
Avocado -. -.. --. ---. -... --....... -. --..... 2 2 2 2 2 3 2 1 3 3 2 1 2 2
Plants -B2 1 2 2 1 2 1 1 3 3 1 2 1 2
Bougainvi1 1 1 1 2 1 1 2 1 1 1 1
0 i-A 1-4 > C) ) Cd cd
f-B3 2 2 2 2 3 3 2 '3 4 43 U U2 C
00 Cd 0 Cd U >. > Cd i U W-
Cashew 1) 2 1 1 2 1 1 1 r-3 1 2 c 1-
Cedar (tabebuia)1 1 1 1 1 2 1 1 2 2 1 -1 1 1
H Coconut palm C1 1 1- 41 1 1 3 2 1 1 1
0- (2) ) Cd 4J- r- U 3 Cd r-4 Ui) 9 A 0
-U ) 0 r cW Cd U Cd ) Q 0 4+J 4+)
Cocoplum3 2 3 2 2 2 2 1 1 3 2 3 1 2
S H V 0 V) W C Cd *-4 Cd 0 c 0 0 -'-

African tulip---------------------------- 3 2 2 2 2 2 2 1 3 2 3 1 2 1 2 2
Alamanda---------------------------------3 1 1 1 1 2 2 1 2 1 3 1 3 1 2 1
Almondyanttree--------------------------- 2 1 1 1 1 2 1 1 1 1 3 1 1 1 1 1
Australianpine-------------------------- 2 1 1 1 1 1 1 1 2 1 3 1 1 1 1 1
Avocado---------------------------------- 2 2 2 2 2 3 2 1 3 1 3 2 1 2 2 2
Bamboo ---------------------------------- 2 2 2 1 2 2 21 1 2 2 3 1 2 1 2 2
Banana, plantain------------------------- 2 1 2 2 1 2 1 3 1 3 1 2 1 2 1
Bougainvillea---------------------------- 1 1 1 1 1 2 1 1 2 1 3 1 1 1 1 1
Breadfruitva -------------------------------3 2 2 2 2 3 31 1 1 2 3 2 3 1 2 2 3 2
Cashewrrytree ------------------------ 3 1 2 1 1 2 1 1 1 1 3 1 2 1 2 1
Cedar (tabebuia)------------------------- 1 1 1 1 2 1 1 2 1 2 1 1 1 1 1
Coconut palm----------------------------- 2 1 1 1 1 2 1 1 1 1 3 2 1 1 1 1
Cocoplumthorn--------------------------- 3 2 3 2 2 2 2 1 1 1 3 2 3 1 2 2
Croton----------------------------------- 2 1 1 1 1 2 2 1 2 1 3 1 2 1 2 1
Custardappleme---------------------------- 3 2 2 2 2 3 2 1 3 2 3 1 3 1 2 2
Date--hogany-----------------------------------2 2 3 2 2 2 2 1 2 1 3 2 2 1 2 2
Flamboyanttree--------------------------- 1 1 1 1 1 1 1 1 1 3 1 1 1 1 1
Frangipani-------------------------------3 1 1 1 1 1 1 1 1 2 1 3 1 1 1 1 1
Genip----------------------------------- 2 1 1 1 1 1 1 1 2 1 3 1 1 1 1 1
Ginger Thomas---------------------------- 1 1 1 1 1 2 1 1 2 1 2 1 1 1 1 1
Gooseberryapefruit-------------------------------2 1 1 1 1 12 2 2 1 2 1 3 1 2 1 1 1
Governorsplum ----------------------------2 1 1 1 1 2 2 1 3 1 3 1 2 1 2 1
Guava----------------------------------- 2 1 1 1 1 1 1 1 2 1 2 1 2 1 1 1
Guavaberrytree--------------------------- 3 1 1 1 1 2 2 1 3 1 3 1 3 2 3 21
HibiscusPomegranate------------------------------- 32 1 1 1 1 2 1 1 2 1 3 1 2 1 2 1
Hogplums de Terre--------------------------- 3 1 1 1 1 1 1 1 3 1 3 1 2 1 1 1
Jerusalemthorn4-------------------------3 2 2 2 2 1 2 2 3 2 3 2 2 2 2 2
Jujube----------------------------------- 2 1 1 1 1 1 1 1 1 1 3 2 2 1 1 1
Lime------------------------------------- 1 1 1 1 1 2 2 1 3 1 2 1 1 1 1 1
Mahogany--------------------------------- 1 1 1 1 1 1 1 1 2 1 2 1 1 1 1 1
Mamey------------------------------------ 2 1 1 1 1 1 1 1 2 1 3 1 2 1 1 1
Mango------------------------------------ 3 1 1 1 1 2 1 1 3 2 3 1 2 1 2 1
Mesple-----------------------------------1 1 1 1 1 2 1 1 2 1 1 2 1 1 1 1
Oleander--------------------------------- 2 1 1 1 1 1 1 1 2 1 3 1 2 1 1 1
Orange, grapefruit----------------------- 3 2 2 2 2 2 2 2 3 2 3 1 2 3 3 2
Ota Haiti-------------------------------- 3 2 2 2 2 2 1 1 1 1 3 2 2 1 1 2
Papaya----------------------------------- 2 1 2 1 1 2 1 1 2 1 3 1 1 1 1 1
Pineapple-------------------------------- 3 1 1 1 2 2 2 2 3 2 3 1 3 2 3 2
Pomegranate------------------------------ 3 1 1 1 2 2 2 1 3 2 3 2 2 1 2 2
Plums de Terre--------------------------- 3 1 1 1 1 2 2 1 3 1 3 1 3 1 2 1





42









TABLE 4.--SUITABILITY OF FRUIT TREES, SHADE TREES, EXOTICS, AND ORNAMENTALS FOR SPECIFIED
SOILS ON ST. THOMAS AND ST. JOHN--CONTINUED

Soils


Plants


Royal palm------------------------------- 3 1 1 1 1 1 2 1 2 1 3 1 2 1 1 1
Seagrape-------------------------------- 2 2 2 2 2 2 2 1 1 2 3 2 2 1 2 2
Soursop--------------------------------- 2 1 1 1 1 2 2 1 3 2 3 1 2 1 2 1
Sugarapple-------------------------------2 1 1 1 1 2 1 1 3 1 3 2 2 1 2 1
Tamarind-------------------------------- 1 1 1 1 1 1 1 1 2 1 3 1 1 1 1 1
Tanya------------------------------- 2 2 2 2 2 2 3 1 3 1 3 2 2 1 2 2
Teak------------------------------------ 3 3 3 1 1 2 1 3 1 3 1 2 1 3 1
Turpentine-myrtle----------------------- 1 1 1 1 1 1 1 1 2 1 3 1 1 1 1 1
West Indian cherry----------------------- 2 1 1 1 1 1 1 1 3 1 3 1 1 1 1 1
Yam------------------------------------- 3 2 3 2 1 3 2 1 2 1 3 2 2 2 1 1








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.


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 increases 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-
dos sourgrass. 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.


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
many fragments of coral and seashells. It occurs
along the seashore. It is very low in moisture-
holding capacity and is very drought.
The potential native plant cover is seashore
dropseed (Sporobolus virginicus).


USE OF THE SOILS FOR WOODLAND3


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


3By Robert W. Nobles, Institute of Tropical
Forestry, United States Forest Service.


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,


382-314 0- 70 4








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.


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
many fragments of coral and seashells. It occurs
along the seashore. It is very low in moisture-
holding capacity and is very drought.
The potential native plant cover is seashore
dropseed (Sporobolus virginicus).


USE OF THE SOILS FOR WOODLAND3


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


3By Robert W. Nobles, Institute of Tropical
Forestry, United States Forest Service.


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,


382-314 0- 70 4








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


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.
Annual 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 all 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 texture 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








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 all 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 texture 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








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 all 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 texture 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








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 all 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 texture 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









TABLE 5.--ESTIMATED

Depth to-- Depth Classification
Seasonal from
Soil and map symbol high sur-
Bedrock water face USDA texture Unified AASHO
table


Aguilita: AgB, AgC2,
AgD, AgE, AgF.

Aguirre: AuA-----------

Coamo: CaB-------------


alluvial land:


Cornhill: CoA----------




Cramer: CrC, CrE, CrF,
CsE2, CsF, CvE.


Descalabrado: DeD, DeE,
DeF.


Diamond: DlB, D1C2-----
For Limestone rock
land part, see Lime-
stone rock land.

Dorothea: DoE, DoF-----



Fraternidad: FcA,
FcC2.


Fredensborg: FrA, FrB,
FrC2.

Glynn: GyB, GyC2-------



Hesselberg: HeA--------


Isaac: IsD2, IsE,


In.

0-10
10-60


Gravelly clay loam------------------------ GC
Soft limestone---------------------------- CL


0-60 Clay------------------------------------ CH


60+

60+




60+


60+




10-20



10-20



8-16




24-37



60+



10-20


60+



10-20




20-72


10+

10+




10+


10+




10+



10+



10+




10+



10+



10+


10+



10+




10+


0-20 Clay, silty clay loam--------------------- MH
20-50 Silt loam, soft marl, and limestone------- CL


0-12
12-30
30-59

0-12
12-17
17-18
18

0-11
11-19
19-36
36


Clay loam---------------------------------
Clay, clay loam---------------------------
Clay loam, sandy loam, and clay-----------

Clay--------------------------------------
Clay--------------------------------------
Limestone--------------------------------
Limestone.

Gravelly clay loam------------------------
Clay--------------------------------------
Clay loam---------------------------------
Volcanic rock.


CH or MH
CH
CH or MH


or ML


or ML

or ML


A-2 or A-4
A-6

A-7

A-7
A-7
A-7





A-4
A-7
A-7
A-6

A-7
A-7


MH or CH A-7
ML or CL A-7


ML or CL A-6
ML or CL A-4


or CH


or ML


See footnotes at end of table.


Co bly
Cb'-


Ft.

10+


0-8
8-24
24-40
40-60




0-9
9-18
18-30
30-48

0-9
9-19
19

0-10
10-19
19

0-10
10-14
14


0-6
6-19
19-36

0-23
23-43
43-62


Clay loam---------------------------------
Clay--------------------------------------
Clay loam---------------------------------
Gravelly clay loam, clay loam, and gravel.




Gravelly clay loam------------------------
Clay loam---------------------------------
Clay--------------------------------------
Gravelly clay-----------------------------

Gravelly clay loam------------------------
Clay and gravelly clay--------------------
Volcanic mudstone.

Clay loam---------------------------------
Silty clay loam--------------------------
Volcanic rock.

Clay loam--------------------------------
Loam-------------------------------------
Limestone.


Clay loam---------------------------------
Clay--------------------------------------
Clay loam---------------------------------

Clay--------------------------------------
Clay--------------------------------------
Clay--------------------------------------


IvD--









PROPERTIES OF THE SOILS

Percentage passing sieve--
Avial


No. 10


55-65
99

100

80-90
85-95
80-90





75-85
100
100
75-85

65-75
90-100


85-95
100


100
100



100
100
100

95-100
100
100

99
99

96
99
99

98
99
50-60


65-75
90-100
85-95


No. 40


No. 200


Permeability


Available
water
capacity


Reaction


1 _____ 1 4- 1 -------


45-55
97

100

75-85
80-90
75-85





70-80
100
100
70-80

60-70
80-90


85-90
100


100
100



100
100
100

90-100
100
100

90-100
95-100

90-100
99
95-100

95-100
99
40-50


60-70
80-90
70-80


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


55-65
65-75
65-75


30-40
56

75-95

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

75-85
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


In./hr.

0.63-2.00
0.63-2.00

0.06-0.20

0.63-2.00
0.20-0.63
0.63-2.00





0.20-0.63
0.20-0.63
0.06-0.20
0.20-0.63

2.00-6.30
0.63-2.00


0.20-0.63
0.63-2.00


0.63-2.00
2.00-6.30



0.63-2.00
0.20-0.63
0.63-2.00

0.06-0.20
0.06-0.20
0.06-0.20

0.20-0.63
0.63-2.00

0.20-0.63
0.20-0.63
0.63-2.00

0.63-2.00
0.63-2.00



2.00-6.30
0.63-2.00
0.63-2.00


In. /in.
of soil
0.15-0.20
0.10-0.15

0.10-0.15

0.15-0.20
0.15-0.20
0.15-0.20





0.15-0.20
0.15-0.20
0.15-0.20
0.15-0.20

0.15-0.20
0.15-0.20


0.15-0.20
0.10-0.15


0.15-0.20
0.10-0.15



0.15-0.20
0.15-0.20
0.15-0.20

0.15-0.20
0.15-0.20
0.15-0.20

0.15-0.20
0.10-0.15

0.15-0.20
0.15-0.20
0.15-0.20

0.10-0.15
0.10-0.15



0.15-0.20
0.15-0.20
0.15-0.20


Shrink-swell potential


Ep

7.9-8.4
7.9-8.4

7.4-8.4

6.6-7.3
7.4-8.4
7.4-8.4





7.4-8.4
7.4-8.4
7.4-8.4
7.4-8.4

6.1-7.3
6.1-7.3


6.1-7.3
6.1-7.3


6.6-7.3
7.4-8.4



5.6-6.5
5.6-6.5
5.6-6.5

7.4-8.4
7.4-8.4
7.4-8.4

7.4-8.4
7.9-8.4

6.6-7.8
6.6-7.8
7.4-8.4

6.6-7.8
6.6-7.8



6.1-7.3
6.1-7.3
6.1-7.3


No. 4


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.









TABLE 5.--ESTIMATED PROPERTIES

Depth to-- Classification
Depth _________
Seasonal from
Soil and map symbol high sur-
Bedrock water face USDA texture Unified AASHO
table


Jacana: JaB, JaC, JaD--




Jaucas: JuB -----------

Lavallee: LaB----------


clayey land:


Leveled marly land:
Lm .

Leveled rocky land:
Lr .

Limestone rock land:
Ls .

Made land: Ma1'2-------

Magens: MgF------------



Parasol: PaB, PaC------




Pozo Blanco: PbC, PbD--


Rock land.
No estimates.

San Anton: SaA, SaC ---



Sion: ScB, ScC---------


Southgate: SgE, SgF,
SrF.


Tidal flats: Tf1'2 ----

Tidal swamp: Ts1'2-----


In.

20-36




60+

60+


60+


60+


At sur-
face.

0-10


60+

60+



60+




60+






60+



10-20


10-20



60+

60+


Ft.

10+




1-4

10+


10+


10+


10+


10+


5+

10+



10+




10+





5+



10+


10+



0-3


In.

0-9
9-17
17-26
26-29


Clay loam---------------------------------
Clay loam---------------------------------
Gravelly clay-----------------------------
Volcanic rock.


or CH
or CH
or CL


0-60 Sand-------------------------------------- SM or SP A-2


0-18 Gravelly clay loam------------------------ CL
18-48 Very gravelly loam------------------------ GC


0-10
10-42
42-84

0-13
13-24
24-40
40-80

0-13
13-18
18-48



0-9
9-32
32-50

0-17
17-50

0-7
7-18
18


Silty clay loam--------------------------- MH
Clay-------------------------------------- MH
Clay loam--------------------------------- ML

Clay loam--------------------------------- ML
Clay-------------------------------------- MH
Clay loam--------------------------------- ML
Saprolite.

Clay loam--------------------------------- CH
Silty clay loam--------------------------- CH
Loam-------------------------------------- CL



Clay loam--------------------------------- MH
Gravelly clay loam------------------------ CL
Clay loam--------------------------------- MH

Clay loam--------------------------------- MH
Soft limestone and marl------------------- CL

Clay loam--------------------------------- MH
Gravelly loam----------------------------- GC
Volcanic rock.


or ML




















or CL


or ML


or CH


A-4
A-2 or A-4

















A-7
A-7
A-6

A-7
A-7
A-7


A-7
A-7
A-6



A-7
A-6
A-7

A-7
A-6

A-7
A-2 or A-4


See footnotes at end of table.


Leveled
Lc .









OF THE SOILS--CONTINUED

Percentage passing sieve--


No. 10


No. 40


No. 200


Permeability


Available
water
capacity


-I + I t


85-95
85-95
100


100

75-85
55-65
















100
100
100

90-100
100
100


100
100
100



85-95
75-85
100

99
99

85-95
55-65


85-90
85-90
100


100

70-80
45-55
















100
100
100

90-100
100
100


100
100
100



85-95
70-90
100

90-100
97

85-95
45-55


80-90
80-90
90-95


85-95

65-75
45-55
















95-100
90-100
90-100

80-90
80-90
70-80


90-100
95-100
85-95



80-90
65-75
90-100

85-95
75-85

80-90
45-55


70-80
70-80
65-75


5-15

70-80
30-40
















85-95
75-95
70-80

60-70
58-70
51-60


70-80
85-95
60-75



70-80
70-80
70-80

75-85
56-65

70-80
30-40


In./hr.

0.20-0.63
0.20-0.63
0.63-2.00


6.30-20.0

0.20-0.63
0.63-2.00
















0.63-2.00
0.63-2.00
0.63-2.00

0.63-2.00
0.20-0.63
0.63-2.00


0.63-2.00
0.63-2.00
0.63-2.00



0.63-2.00
0.63-2.00
0.63-2.00

0.20-0.63
0.63-2.00

0.63-2.00
2.00-6.30


Reaction


In./in.
of soil
0.15-0.20
0.15-0.20
0.10-0.15


0.05-0.10

0.15-0.20
0.10-0.15
















0.10-0.15
0.15-0.20
0.10-0.15

0.10-0.15
0.15-0.20
0.10-0.15


0.10-0.15
0.15-0.20
0.10-0.15



0.15-0.20
0.10-0.15
0.15-0.20

0.15-0.20
0.10-0.15

0.15-0.20
0.10-0.15


Shrink-swell potential


pH

6.1-7.3
6.1-7.3
6.1-7.3


7.4-8.4

6.1-7.3
6.6-7.8
















5.1-6.0
4.5-5.5
4.5-5.5

5.1-5.5
6.6-7.3
6.6-7.8


6.6-7.8
7.4-8.4
7.4-8.4



6.1-7.3
6.6-8.4
7.4-8.4

7.4-8.4
7.9-8.4

5.1-6.0
5.6-6.5


No. 4


High.
Moderate.
Moderate.


Very low.

Moderate.
Low.
















Low.
Low.
Low.

Moderate.
High.
Moderate.


Moderate.
Moderate.
Moderate.



Moderate.
Low.
Moderate.

Moderate.
Moderate.

Moderate.
Low.














Soil and map symbol


TABLE 5.--ESTIMATED PROPERTIES


Depth to--

Seasonal
high
Bedrock water
table


Depth
from
sur-
face


Classification


USDA texture


In. Ft. In.

Victory: VcD, VcE------ 60+ 10+ 0-22 Clay loam---------------------------------

Volcanic rock land: 0-6 10+
Vr .


Subject to flooding.









.dE SOILS--CONTINUED
---------------
Percentage passing sieve--



No. 4 No. 10 No. 40 No. 200


T r I


90-100


65-75


Permeability


In./hr.

0.63-2.00


Available
water
capacity


In./in.
of soil
0.15-0.20


Reaction


5.6-6.5
5.6-6.5


Shrink-swell potential





Moderate.


2Material variable. Onsite determination is necessary.











TABLE 6.--INTERPRETATION OF ENGINEERING PROPERTIES OF THE SOILS

Soil limitations for
Suitability as source of-- Soil features affecting-- sewage disposal

Soil and Farm ponds
map symbols Topsoil Road fill Highway location Foundations for Septic tank Sewage lagoons
Reservoir area Embankment low buildings filter fields


Aguilita: AgB,
AgC2, AgD, AgE,
AgF.






Aguirre: AuA---


Poor: gravel
and cobble-
stones.






Poor: plas-
tic clay.


Coamo: CaB----- I Good---------


Cobbly alluvial
land: Cb.



Cornhill: CoA--


Poor: stones
and cobble-
stones.


Good---------


Fair: cobble-
stones and
stones.






Poor: very
high shrink-
swell poten-
tial.



Fair: moderate
shrink-swell
potential.






Poor: stones
and cobble-
stones.


Fair in upper-
most 18 inches;
poor at a depth
of 18 to 30
inches; very
high shrink-
swell poten-
tial.


Erodible if ex-
posed on embank-
ments; need for
cuts and fills;
stones in places


Unstable: plas
tic clay.






All features
favorable.







Stones hinder
hauling and
grading.


Plasticity of
underlying
layers.


Slope reduces
storage poten-
tial.


- All features
favorable.


Pervious ma-
terial and
layers.






Pervious
layers.



Gravelly
layers; seep-
age.


Fair sta-
bility;
fair com-
paction;
high com-
pressi-
bility.

Very high
shrink-
swell po-
tential;
poor com-
paction.

Fair sta-
bility;
fair com-
paction;
high com-
pressi-
bility.

Stones and
cobble-
stones.


Very high
shrink-
swell po-
tential;
poor com-
paction.


Fair stability;
fair compac-
tion; high com-
pressibility.




Very high
shrink-swell
potential.




Fair stability;
fair compac-
tion; high com-
pressibility.




Flood hazard;
stones and
cobblestones.


Poor stability
and very high
shrink-swell
potential at a
depth of 18 to
30 inches.


Severe if
slope is more
than 10 per-
cent; moder-
ate if 5 to
10 percent.


Severe: slow
permeability.






Slight-------








Severe: flood
hazard.



Severe: slow
permeability
at a depth of
18 to 36
inches.


Severe if
slope is more
than 7 percent;
moderate if 2
to 7 percent.



Moderate: un-
stable material
for embank-
ments.



Moderate: slope
is more than 2
percent; fair
stability for
embankments.



Severe: flood
hazard;
cobblestones
and stones.

Slight.










Soil limitations for

Suitability as source of-- Soil features affecting-- sewage disposal

Soil and Farm ponds Se
map symbols Topsoil Road fill Highway location Foundations for Septic tank Sewage lagoons
Reservoir area Embankment low buildings filter fields


Cramer: CrC,
CrE, CrF, CsE2,
CsF, CvE.







Descalabrado:
DeD, DeE, DeF.





Diamond: DlB,
D1C2.
For limestone
rock land
part, see
Limestone
rock land.

Dorothea: DoE,
DoF.







Fraternidad:
FcA, FcC2.


Poor: gravel
and stones;
difficult to
obtain be-
cause of to-
pography.



Fair to poor,
depending on
accessibil-
ity.


Poor: shallow
over hard
limestone;
stones; lime-
stone out-
crops.


Fair to poor,
depending on
accessibil-
ity.


Poor: shallow
over bedrock;
poor accessi-
bility because
of slope.





Poor: shallow
over rock; poor
accessibility
because of
slope.

Poor: shallow
over hard lime-
stone.






Fair: poor ac-
cessibility
because of
slope.




Poor: high
shrink-swell
potential.


Bedrock at a
depth of 10 to 20
inches; need for
cuts and fills.






Shallow over bed-
rock; need for
cuts and fills.



Shallow over hard
limestone.







Erodible if ex-
posed on embank-
ments; need for
cuts and fills.


plastic


Fractured
rock; high
seepage poten-
tial; slope.






Fractured rock;
high seepage
potential;
slope.


Hard limestone;
high seepage
potential.






Slope reduces
storage poten-
tial.






All features
favorable.


Fair sta-
bility;
fair com-
paction;
limited
volume of
material;
shallow.

Limited
volume of
material;
poor sta-
bility.

Limited
volume of
material;
stones;
limestone
outcrops.


Poor sta-
bility;
poor com-
paction;
high com-
pressi-
bility.

High
volume
change;
poor com-
paction.


Shallow over
bedrock.








Shallow over
bedrock.




Shallow over
hard limestone.







Poor stability;
high compressi-
bility in sub-
soil.





High shrink-
swell poten-
tial.


Severe: shal-
low over bed-
rock.







Severe: shal-
low over bed-
rock; steep
slope.


Severe: shal-
low over hard
limestone.


Severe:
slope.


steep


Severe: slow
permeability.


Severe: slope
more than 7
percent; less
than 20 inches
over bedrock.





Severe: slope
more than 7
percent; less
than 20 inches
over bedrock.

Severe: less
than 20 inches
over hard
limestone.




Severe: steep
slope.







Moderate: high
volume change;
unstable mate-
rial for em-
bankments.


Poor:
clay.


plastic


Unstable,
clay.











TABLE 6.--INTERPRETATION OF ENGINEERING PROPERTIES OF THE SOILS--Continued


Soil limitations for
Suitability as source of-- Soil features affecting-- sewage disposal

Soil and Farm ponds
map symbols Topsoil Road fill Highway location Foundations for Septic tank Sewage lagoons
Reservoir area Embankment low buildings filter fields


Fredensborg:
FrA, FrB, FrC2.







Glynn: GyB,
GyC2.







Hesselberg:
HeA.







Isaac: IsD2,
IsE, IvD.








Jacana: JaB,
JaC, JaD.


Good--------








Fair: shallow
over hard
limestone.






Fair to poor,
depending on
amount of
gravel and
accessibil-
ity.



Fair: moder-
ately deep
over bedrock;
accessibility
of slope.


Fair:
clay.


Plastic clay in
surface layer;
underlying soft
limestone easy to
haul and exca-
vate.


Plastic subsoil;
moderate to high
shrink-swell
potential.


All features
favorable.







Seepage through
gravelly lay-
ers.


plastic


Poor in soil
material; high
shrink-swell
potential; fair
in underlying
soft limestone.


Fair: moderate
to high shrink-
swell poten-
tial.




Poor: shallow
over hard lime-
stone; high
shrink-swell
potential.



Fair to poor,
depending on
depth to bed-
rock; moderate
shrink-swell
potential.



Poor: moderate-
ly deep over
bedrock; high
to moderate
shrink-swell
potential.


hard limestone
that has high
seepage poten-
tial.



20 to 72 inches
to fractured
rock; seepage
potential;
slope reduces
storage poten-
tial.


Fractured
rock; high
seepage; slope
reduces stor-
age potential.


Poor sta-
bility;
poor com-
paction;
high com-
pressi-
bility.

Poor sta-
bility;
poor com-
paction.


Limited


Poor stability
and poor com-
paction in sur-
face layer;
fair in under-
lying soft
limestone.

Poor stability;
poor compac-
tion.


Shallow over


volume of hard limestone.


material;
poor sta-
bility and
compac-
tion.

Fair sta-
bility;
fair com-
paction;
limited
volume of
material
at source.

Poor sta-
bility and
compac-
tion;
limited
volume of
material
at source.


Fair stability;
fair compac-
tion; fair com-
pressibility.






20 to 36 inches
to bedrock.


Slight: mod-
erately slow
permeability
in surface
layer; slight
limitation
below.

Moderate:
moderately
slow permea-
bility in
upper 30
inches.


Moderate: poor
stability for
embankments;
severe if
slope is more
than 7 per-
cent.

Moderate: poor
stability for
embankments;
severe if;
slope is more
than 7 per-
cent.


Severe: shal- Severe: less
low over hard than 20 inches
limestone, over hard
limestone.


Severe if
slope is more
than 10 per-
cent; less
than 4 feet
to bedrock.



Severe: less
than 4 feet
to bedrock.


Severe if
slope is more
than 7 per-
cent; moder-
ately deep
over bedrock.



Severe: less
than 4 feet to
bedrock.


Hard limestone atiShallow over


a depth of 10 to
20 inches.






Bedrock at a
depth of 20 to 72
inches; need for
cuts and fills.






Bedrock at a
depth of 20 to 36
inches; need for
cuts and fills.













Soil and
map symbols


Jaucas: JuB-----





Lavallee: LaB---









Leveled clayey
land: Lc.






Leveled marly
land: Lm.






Leveled rocky
land: Lr.


Suitability as source of--


Soil features affecting--


Soil limitations for
sewage disposal


- -_ r


Topsoil


Road fill


Farm ponds
Highway locations I


Reservoir area


Embankment


Foundations for Septic tank
low buildings filter fields


I I + I I t t


Poor: low
productivity;
low available
moisture ca-
pacity.


Good if con-
fined.


Fair: gravel- Good-----------


Poor: plastic
clay.






Poor: low
productivity.


Poor: plastic
clay.






Fair-----------


Poor: exposed Poor: exposed
bedrock. bedrock.


Subject to floo
ing during high
tide.



All features
favorable.








Unstable, plas-
tic clay.






All features
favorable.






Bedrock at or
near surface.


d- Very pervious
material.


Gravelly
layers; seep-
age.






All features
favorable.






All features
favorable.






Practice not
applicable.


Poor sta-
bility;
piping;
rapid per-
meability.

Fair sta-
bility.
good com-
paction;
slight to
medium
compressi-
bility.

Poor sta-
bility;
poor com-
paction;
high com-
pressi-
bility.

Fair sta-
bility;
fair com-
paction;
medium
compressi-
bility.

Practice
not appli-
cable.


Poor stability
unless con-
fined; low
shear strength.


Fair stability;
good compac-
tion; medium
compressibil-
ity.




High shrink-
swell poten-
tial.





Fair stability;
fair compac-
tion; fair com-
pressibility.




Hard rock at oi
near surface.


Severe: flood
hazard; high
water table;
pollution haz-
ard.

Slight-------


Sewage lagoons


Severe: very
rapid perme-
ability; poor
stability for
embankments.

Moderate: 20
to 50 percent
gravel.


Severe: slow Moderate: poor
permeability, stability for
embankments.


Moderate:
moderate per-
meability.





Severe: hard
rock at or
near surface.


Practice not
applicable.






Severe: bed-
rock at or
near surface.


I










TABLE 6.--INTERPRETATION OF ENGINEERING PROPERTIES OF THE SOILS--Continued


Soil limitations for
Suitability as source of-- Soil features affecting-- sewage disposal

Soil and Farm ponds
map symbols Topsoil Road fill Highway location Foundations for Septic tank Sewage lagoons
Reservoir area Embankment low buildings filter fields


Limestone rock
land: Ls.



Made land: Ma---








Magens: MgF-----










Parasol: PaB,
PaC.







Pozo Blanco:
PbC, PbD.


Poor: exposed Poor: exposed
limestone, limestone.


Limestone at or
near surface.


soil Good----------- May be flooded


Fair: diffi-
cult to ob-
tain because
of slope.







Good--------








Good to fair,
depending on
accessibil-
ity.


Fair: poor ac-
cessibility be-
cause of slope.








Fair: plastic
clay subsoil.







Fair: moderate
shrink-swell
potential.


during high tide.







Erodible if ex-
posed on road-
banks; need for
cuts and fills;
easy to haul and
excavate.




Plastic, unstable
subsoil.







Erodible if ex-
posed on road-
banks; need for
cuts and fills.


Practice not
applicable.



Very pervious
material.







Slope reduces
storage poten-
tial.








Seepage in
underlying
layers.





Pervious
underlying
layers; slope
reduces
storage poten-
tial.


Practice
not appli-
cable.


Poor sta-
bility;
fair com-
paction;
rapid per-
meability;
piping.

Fair to
poor sta-
bility;
fair to
poor com-
paction;
high com-
pressi-
bility.

Fair to
poor sta-
bility;
medium to
high com-
pressi-
bility.

Poor sta-
bility in
uppermost
18 inches;
fair to
good be-
low.


Limestone at or
near surface.



Poor stability;
fair compac-
tion; subject
to piping;
rapid permea-
bility.


Fair stability;
fair compac-
tion; high com-
pressibility.







High compressi-
bility; fair to
poor stability.






High compressi-
bility and poor
stability in
uppermost 18
inches; fair to
good below.


Severe: lime-
stone rock at
or near sur-
face.

Slight-------


Severe: lime-
stone at or
near surface.


Severe: very
rapid perme-
ability.


Severe: steep Severe: steep
slope, slope.


Moderate:
moderate per-
meability.






Moderate:
moderate per-
meability;
severe if
slope is more
than 10 per-
cent.


Moderate: un-
stable mate-
rial for em-
bankments; se-
vere if slope
is more than
7 percent.

Moderate: un-
stable mate-
rial for em-
bankments;
severe if
slope is more
than 7 per-
cent.


Poor: no
material
available









Soil limitations for
Suitability as source of-- Soil features affecting-- sewage disposal

Soil and Farm ponds
map symbols Topsoil Road fill Highway location Foundations for Septic tank Sewage lagoons
Reservoir area Embankment low buildings filter fields


Rock land.
No interpre-
tations.

San Anton: SaA,
SaC.











Sion: ScB, ScC--









Southgate: SgE,
SgF, SrF.







Tidal flats:
Tf.


Tidal swamp: Ts-


Good--------













Fair: shallow
over soft
limestone.







Fair to poor,
depending on
accessibil-
ity.




Poor: toxic
salts.


Poor: toxic
salts.


Fair: moderate
shrink-swell
potential.










Fair: moderate
shrink-swell
potential.







Poor: shallow
over rock.







Poor: shallow
over water
table.

Poor: poorly
drained;
usually flood-
ed.


Need for cuts and
fills on steeper
slopes.










Moderately plas-
tic surface
layer.







Bedrock at a
depth of 10 to 20
inches; erodible
if exposed on
roadbanks; need
for cuts and
fills.

High water table;
subject to fre-
quent flooding.


Gravelly
layers; seep-
age.










All features
favorable.








Fractured
rock; seepage;
slope reduces
storage poten-
tial.



High water
table.


Usually flooded-- Inundated------


Poor sta-
bility;
poor com-
paction.









Poor com-
paction in
surface
layer;
fair to
good be-
low.


Shallow
over rock;
limited
volume of
material
at source.


Variable--




Organic
material;
variable.


High compressi-
bility; poor
compaction.










Poor compaction
and poor sta-
bility in sur-
face layer;
fair in under-
lying layers.



Shallow over
bedrock.







High water
table.


High water
table; usually
flooded.


Moderate to
severe: flood
hazard; mod-
erate perme-
ability.








Severe in
surface
layer; moder-
ate below;
moderate per-
meability.



Severe: bed-
rock at a
depth of 10
to 20 inches;
steep slope.



Severe: high
water table.


Severe: high
water table;
flooding.


Moderate: 9-
to 38-inch
layer more
than 20 per-
cent gravel;
moderate per-
meability;
severe if
slope is more
than 7 per-
cent.

Moderate: sur-
face layer un-
stable for em-
bankments;
severe if
slope is more
than 7 per-
cent.

Severe: steep
slope; bedrock
at a depth of
less than 20
inches.



Severe: high
water table.


Severe: high
water table.









TABLE 6.--INTERPRETATION OF ENGINEERING PROPERTIES OF THE SOILS--Continued

Soil limitations for
Suitability as source of-- Soil features affecting-- sewage disposal

Soil and Farm ponds
map symbols Topsoil Road fill Highway location Foundations for Septic tank Sewage lagoons
Reservoir area Embankment low buildings filter fields

Victory: VcD, Fair to poor, Fair: poor ac- Need for cuts and Slope reduces Poor sta- Poor compac- Severe: steep Severe: slope
VcE. depending on cessibility fills; erodible storage poten- ability; tion; poor sta- slope, more than 7
accessibil- because of if exposed on em- tial. poor com- ability; medium percent.
ity. slope. bankments. action. to high com-
pressibility.

Volcanic rock Poor: exposed Poor: exposed Bedrock at or Practice not Practice Hard rock at or Bedrock at or Severe: bed-
land: Vr. volcanic bedrock, near surface, applicable, not appli- near surface, near surface, rock at or
rock. cable. near surface.








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 0 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 for 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








TABLE 7.--ENGINEERING


[Tests made by Bureau of Public Roads (BPR) in accordance with standard

Mechanical analysis

Percentage passing sieve--
Soil name and location Parent material Depth
No. 4 No. 10
1-in. 3/4-in. (4.7 m.1) (2.0 mm.)
In.
Cramer gravelly clay loam:
1.8 miles NW. of Annaly and 100 feet to Volcanic rocks 0-14 100 91 72 67
the right of Scenic Drive. (Ortho) (Caledonia forma- 14-20 98 98 93 83
tion). 20-32 92 85 60 52

0.15 mile S. of Centerline Rd. and 50 Sediments derived 0-8 98 97 86 77
feet E. of main entrance to Cotton from basic volcanic 8-21 --- --- --- 100
Valley. (Thick B2t horizon) rocks and local 21-27 100 99 88 74
residuum.
Descalabrado clay loam:
1.75 miles W. of Fountain-LaVallee and Basic volcanic 0-10 95 93 89 87
50 feet NE. of Scenic Drive. (Ortho) rocks. 14-30 -- --- --- 100

Fraternidad clay:
0.3 mile W. along N. side of Lower Love Sediments derived 0-6 --- --- 98 94
and 400 feet N. of farm road. (Ortho) from residuum of 23-31 --- --- --- 100
volcanic and lime- 43-62 -- --- --- 100
stone rocks.
Fredensborg clay:
0.25 mile W. of Kingshill Police Station Alluvium derived 0-16 --- 100 99 94
and 150 feet W. and 75 feet N. of road from limestone. 22-50 -- --- 99 97
intersection. (Ortho)

Glynn clay loam:
300 feet S. of church in SW. corner of Alluvium derived 0-10 --- 100 96 94
Grove Place and 60 feet W. and 30 feet from volcanic 15-26 --- --- 99 99
N. of light pole. (Ortho) rocks. 50-59 --- --- 99 97

Hesselberg clay:
0.7 mile W. of S. entrance to airport Residuum from 0-7 99 99 98 97
and 470 feet S. on secondary road and limestone. 12-17 --- --- 99 99
50 feet W. of road. (Ortho) 17-18 97 92 55 46

Parasol clay loam:
1.3 miles N. of oil road and 100 feet Sediments derived 0-7 95 95 95 94
S. and 75 feet W. of gate on road to from intrusive ig- 13-24 --- -- --- 100
River. (Ortho) neous rocks (Gab- 24-40 --- --- --- 100
bro).

1According 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 by 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,









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-- Liquid Plastic-
limit ity AASHO Unified
No. 40 No. 200 index
(0.042 mm.) (0.074 mm.) 0.05 mm. 0.02 mm. 0.005 mm. 0.002 mm.
Pct.

58 49 48 44 32 23 60 20 A-7-5(8) GM
69 60 58 55 44 38 44 21 A-7-6(10) CL
40 35 34 32 27 23 46 22 A-2-7(2) GC

62 48 46 43 36 28 46 20 A-7-6(6) SM or SC
87 68 66 63 54 47 56 30 A-7-6(17) CH
47 30 28 24 19 16 38 17 A-2-6(l) SC


84 76 73 63 44 32 58 26 A-7-5(18) MH or CH
92 69 63 51 30 23 42 15 A-7-6(9) ML or CL


87 75 71 57 42 35 52 28 A-7-6(18) CH
98 91 89 81 66 56 85 57 A-7-6(20) CH
94 86 83 75 61 51 79 54 A-7-6(20) CH


89 81 78 72 63 56 75 39 A-7-5(20) MH or CH
82 56 53 48 40 31 36 15 A-6(6) CL



86 70 66 56 38 30 41 19 A-7-6(11) CL
97 89 86 77 63 56 76 44 A-7-5(20) CH
94 83 80 70 53 45 60 37 A-7-6(20) CH


91 85 83 72 59 50 92 46 A-7-5(20) MH
97 94 92 86 79 75 106 58 A-7-5(20) MH
30 17 16 15 14 12 36 6 A-l-b(0) GM


83 60 56 48 37 34 50 22 A-7-6(11) ML or CL
81 58 55 48 39 34 56 25 A-7-5(12) MH or CH
76 51 49 42 30 25 50 23 A-7-6(9) ML or CL


and


the material coarser than 2 millimeters in diameter is excluded from calculations of grain-size fractions.
mechanical analysis data used in this table are not suitable for naming textural classes for soils.


SCS 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.








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.


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.








TABLE 8.--DEGREE AND KIND OF LIMITATION FOR SPECIFIED RECREATIONAL USE


Intensive play Paths and
Soil Golf fairways Campsites Picnic areas areas trails


Aguilita:
AgB-------------



AgC2------------



AgD-------------



AgE-------------



AgF-------------



Aguirre: AuA-------


Severe: coarse
fragments.


Severe: coarse
fragments.


Severe: coarse
fragments;
slope.

Severe: coarse
fragments;
slope.

Severe: coarse
fragments;
slope.

Severe: poor
trafficability.


Coamo: CaB--------- Slight-----------


Cobbly alluvial
land: Cb.

Cornhill: CoA------

Cramer:
CrC-------------



CrE------------



CrF-------------



CsE2-------------



CsF-------------



CvE--------------


Severe: coarse
fragments.

Severe: coarse
fragments.

Severe: 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:
fragments. texture.


Moderate: slope;
coarse frag-
ments.


Moderate: slope;
soil texture.


Moderate: coarse Moderate: slope;
fragments; soil texture.
slope.

Severe: slope--- Severe: slope----



Severe: slope--- Severe: slope----



Severe: wetness; Severe: wetness;


flooding.


Moderate: soil
texture.

Severe: flood-
ing.


soil texture.

Moderate: soil
texture.

Severe: flood-
ing.


Moderate: coarse Moderate:
fragments. texture.


Severe: coarse
fragments.


Severe: coarse
fragments;
slope.

Severe: coarse
fragments;
slope.

Severe: stoni-
ness; slope.


Severe: stoni-
ness; slope.


Severe: coarse
fragments;
slope.


soil


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.


Moderate: soil
texture.


Moderate: soil
texture.


Moderate: slope;
soil texture.


Moderate: slope;
soil texture.


Severe: slope.


Severe: wetness; Severe: wetness;
soil texture, 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.


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.









TABLE 8.--DEGREE AND KIND OF LIMITATION FOR SPECIFIED RECREATIONAL USE--CONTINUED


Intensive play Paths and
Soil Golf fairways Campsites Picnic areas areas trails


Descalabrado:
DeD-------------


DeE-------------


DeF-------------

Diamond:
DlB--------------


D1C2------------

Dorothea:
DoE-------------


DoF-------------

Fraternidad: FcA,
FcC2.

Fredensborg:
FrA, FrB--------


FrC2------------


Glynn:
GyB-------------


GyC2-----------


Hesselberg: HeA----

Isaac:
IsD2------------


IsE-------------


IvD--------------


Jacana:
JaB-------------


JaC-------------


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.

Slight----------


Moderate: slope--


Moderate: fair
trafficability.

Severe: slope----


Severe: slope----


Severe: coarse
fragments.


Slight----------


Moderate: slope--


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.

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.


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: slope---


Severe: slope---



Moderate: slope;
soil texture.

Severe: slope---


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.


JaD--------------Severe: slope---- Moderate: slope;
soil texture.


Severe: slope--- Moderate: slope








TABLE 8.--DEGREE AND KIND OF LIMITATION FOR SPECIFIED RECREATIONAL USE--CONTINUED


Soil

Jaucas: JuB--------



Lavallee: LaB------


Leveled clayey
land: Lc.

Leveled marly land:
Lm.

Leveled rocky land:
Lr.

Limestone rock
land: Ls.

Made land: Ma------


Magens: MgF--------

Parasol:
PaB--------------


PaC-------------

Pozo Blanco:
PbC-------------


Golf fairways


Campsites


Picnic areas


Intensive play
areas


I + T


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: soil
texture.


Moderate: coarse
fragments.

Severe: soil
texture.

Moderate: soil
texture.

Very severe:
rockiness.

Very severe:
rockiness.

Severe: soil
texture.


Severe: slope---- Severe: slope---


Slight----------


Moderate: slope--


Moderate: slope-,


PbD--------------Severe: slope----


Rock land.
No interpreta-
tions.

San Anton:
SaA-------------


SaC-------------

Sion:
ScB-------------


ScC-------------

Southgate:
SgE-------------


Slight----------


Moderate: slope--


Slight----------


Moderate: slope--


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: slope---


SgF-------------- Severe: slope---- Severe: slope---


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:
ing.

Moderate:


flood-


slope--


Moderate: soil
texture.

Moderate: slope;
soil texture.

Severe: slope----


Severe: slope----


Severe: soil
texture.


Severe: coarse
fragments.

Severe: soil
texture.

Moderate: soil
texture.

Very severe:
rockiness.

Very severe:
rockiness.

Severe: soil
texture.


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--- 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---


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.








TABLE 8.--DEGREE AND KIND OF LIMITATION FOR SPECIFIED RECREATIONAL USE--CONTINUED

Intensive play Paths and
Soil Golf fairways Campsites Picnic areas areas trails

Southgate: cont.
SrF-------------- Severe: slope; Severe: slope; Severe: slope; Severe: slope; Severe: rocki-
For Rock land coarse fragments. rockiness. rockiness. rockiness. ness.
part of SrF,
see Rock land.

Tidal flats: Tf---- Severe: poor Very severe: Severe: flood- Very severe: Very severe:
trafficability. flooding. ing. flooding, flooding.

Tidal swamp: Ts---- Severe: poor Very severe: Severe: flood- Very severe: Very severe:
trafficability. flooding. ing. flooding, flooding.
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--- Moderate: slope;
soil texture.

Volcanic rock land: Severe: coarse Very severe: Severe: rocki- Very severe: Severe: rocki-
Vr. fragments; slope, rockiness. ness. rockiness. ness.








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.


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


382-314 0- 70 6








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.


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


382-314 0- 70 6








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.


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


382-314 0- 70 6








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.


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


382-314 0- 70 6








soils. There are only small variations in tempera-
ture, no more than 50 or 70 between the coldest and
the warmest months. The average annual temperature
is 79.70 F. The average temperature in January is
76.90, and that in July is 82.60. 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


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.


Representative 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.




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