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Title: Florida quarterly bulletin of the Agricultural Department
ALL VOLUMES CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00077083/00084
 Material Information
Title: Florida quarterly bulletin of the Agricultural Department
Uniform Title: Avocado and mango propagation and culture
Tomato growing in Florida
Dasheen its uses and culture
Report of the Chemical Division
Alternate Title: Florida quarterly bulletin, Department of Agriculture
Florida quarterly bulletin of the Department of Agriculture
Physical Description: v. : ill. (some fold) ; 23 cm.
Language: English
Creator: Florida -- Dept. of Agriculture
Publisher: s.n.
Place of Publication: Tallahassee Fla
Publication Date: -1921
Frequency: quarterly
monthly[ former 1901- sept. 1905]
regular
 Subjects
Subject: Agriculture -- Periodicals -- Florida   ( lcsh )
Agricultural industries -- Statistics -- Periodicals -- Florida   ( lcsh )
Genre: periodical   ( marcgt )
 Notes
Dates or Sequential Designation: -v. 31, no. 3 (July 1, 1921).
General Note: Description based on: Vol. 19, no. 2 (Apr. 1, 1909); title from cover.
General Note: Many issue number 1's are the Report of the Chemical Division.
General Note: Vol. 31, no. 3 has supplements with distinctive titles : Avocado and mango propagation and culture, Tomato growing in Florida, and: The Dasheen; its uses and culture.
 Record Information
Bibliographic ID: UF00077083
Volume ID: VID00084
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 28473206
 Related Items

Table of Contents
    Cover
        Page 1
        Page 2
    County map of Florida
        Page 3
        Page 4
    Classification of the soils of Florida
        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
        Page 33
        Page 34
        Page 35
        Page 36
        Page 37
        Page 38
        Page 39
        Page 40
        Page 41
        Page 42
        Page 43
        Page 44
        Page 45
        Page 46
        Page 47
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        Page 55
Full Text




VOLUME 28


NUMBER 4


SjUPPLEMENT TO QUARTERLY BULLETIN OF THE

DEPARTMENT OF AGRICULTURE
STATE OF FLORIDA

W. A. McRAE. Commissioner


CLASSIFICATION OF THE SOILS OF FLORIDA.

BY E. H. SELLARDS, STATE GEOLOGIST.


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CLASSIFICATION OF THE SOILS OF FLORIDA.

BY E. H. SELLARDS, STATE GEOLOGIST.








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CLASSIFICATION OF THE SOILS OF
FLORIDA




E. H. SELLARDS, State Geologist.


CONTENTS.

Definition of Soil.
Origin of Soil.
Physical basis of soil.
Igneous rocks.
Sedimentary rocks.
Disintegration of Rocks.
Changes of temperature.
Frost and freezing.
Wind.
Water.
Plants and animals.
Accumulation of disintegrated material.
Influence of drainage condition on soils.
Organic matter.
Color of soil.
The water table.
The hardpan.
The translocation of clay particles.
Plant food derived from the soil.
The soils of Florida.
Parent formations from which derived.
Conditions under which they have originated.
Climatic conditions to which subjected since their formation.
Classification of soils in general.
Residual soils.
Transported soils.
Colluvial soils.
Common terms applied to soils.
Specific and technical soil names.
Classification of the soils of Florida.
Pine lands.
Rolling, upland or well-drained pine lands.
Flatwoods.
Palmetto flatwoods.
Open flatwoods.
Pine lands of the Miami Limestone.
Hammock lands.
Calcareous hammock.
Clay hammock.












Sand hills.
Sand dunes.
Scrub.
Prairie and savanna.
Alluvial lands.
Swamps.
Marsh and muck lands.

Natural physiographic and soil divisions of the State.
West Florida pinelands
West Florida coastal belt.
Eucnee valley hammock lands.
Holmes valley hammock lands.
West Florida limestone belt.
The Apalachicola flatwoods.
The middle Florida hammock belt.
Middle Florida flatwoods.
Gulf hammock belt.
Erosion valley of the Suwannee river.
Hard rock phosphate belt.
Lake region.
East Florida pine lands.
Atlantic coast hammock belt.
Atlantic coast dunes.
South Florida pine lands.
Southern Gulf coast dunes.
The Everglade muck lands.
The Miami limestone belt.
Dade county prairie belt.
Mangrove swamps.
The Florida keys.




DEFINITION OF SOIL.


Soil may be defined as the relatively thin covering of
fragmental material that more or less completely mantles
the surface of the earth and serves as an anchorage for
and contributes to the growth of plants.

ORIGIN OF SOIL.


Soils originate from the decay and disintegration of
pre-existing rocks. They are therefore largely inorganic
in character, although to the inorganic material there is
added more or less organic matter resulting from the de-











cay of vegetable and animal life. While the mineral or
inorganic material usually predominates, some soils, as
those derived from muck and peat deposits, consist largely
of organic matter.

PHYSICAL BASIS OF SOILS.


The average soils consist chiefly of an intimate admix-
ture of clay particles and sand grains with more or less
gravel. However, many other minerals occur in soils,
and almost any mineral that is relatively insoluble and
not easily decomposed may be expected as a soil ingre-
dient. On the other hand, under normal conditions the
readily soluble minerals are largely removed by rain water
while the unstable minerals are decomposed. It is only
in the arid regions that the water soluble minerals ac-
cumulate in soils.

ROCKS OF THE EARTH'S CRUST.

The rocks of the earth's crust from which soils are form-
ed may be grouped under two main divisions, igneous
(or primary) and sedimentary (or secondary). The
igneous rocks are those which appear to have cooled from
a molten condition. The earliest rocks of the earth's
crust are of this type, as well as the more recent materials
brought up from deep within the earth by volcanic action.
Secondary, or sedimentary rocks on the contrary, are
those which have been derived either directly or indirectly
from igneous rocks. Chemical changes, however, are going
on incessantly within the earth and affect all rock forma-
tions. Chemical and physical forces have in many in-
stances so profoundly altered formations that it is no
longer possible to determine whether they were originally
igneous or sedimentary. For these the term metamorphic
rock has often been used











Igneous Rocks:-The Igneous rocks are very complex
chemically, and include most of the chemical elements.
In structure and mineralogical composition they are like-
wise variable. The structure is determined largely by the
rate of cooling and other conditions under which the rocks
were formed. When cooled quickly the time necessary for
crystallization is not available and the rocks are of a
glassy texture. When cooled more slowly various minerals
are formed and the rock assumes a more or less distinctly
crytallized structure. Volcanic ash and obsidian are
examples of rapidly cooled rock; while the granites and
similar coarsely crystallized rocks may result from a
molten mass cooling slowly deep within the earth and
under great pressure, which latter condition favors a more
perfect crystallization.
Mineralogically the igneous rocks are likewise complex.
The presence of the chemical elements under varying con-
ditions of cooling give conditions favorable for the forma-
tion of many minerals. The leading minerals formed
under these conditions are the silicates, of which there
are a great number. In addition to the silicates, sul-
phates, sulphides, phosphates, phosphides, chlorides,
oxides and other minerals abound in these rock. Among
the mineral in the igneous rocks, quartz is to be noted
in this connection as the mineral which, owing to its
abundance and great resistance, remains as sand even
after the disintegration and disappearance of most of
the associated minerals. The feldspars break up through
decay, furnishing the clayey element in soils, while from
certain of the feldspars are derived also the potash so
necessary to soil fertility. The ferromagnesian silicates
include pyroxenes, amphiboles and mica. From these
minerals is derived the iron which is so large an element
in the coloring of soils, as well as various other bases,
a calcium and magnesium. Phosphorous is present in
igneous rocks, although usually in small quantities in the
form of apatite.










Secondary or Sedimentary Rocks:-The secondary, de-
rived or sedimentary rocks are grouped into several
classes determined by their manner of formation and
chemical composition. These rocks are much less complex
both in structure and in chemical and mineralogical com-
position than the igneous rocks. They are derived from
other rocks and in the process of reworking there is neces-
sarily a selective separation of materials. The more
soluble constituents of the original rocks are carried to
the rivers, lakes and the ocean in solution, while the less
soluble are mechanically transported and are separated
according to specific gravity and size of particles.
Such common rocks as shales, sandstone, and conglome-
rates represent material mechanically transported and re-
accumulated. The transporting agents are chiefly run-
ning water and the wind. The shales represent the finer
sediments carried as mud, accumulated in quiet water and
subsequently consolidated. The sandstones are the result
of the accumulation of sand either by water or by the
wind. After being accumulated these sands may become
cemented and thus form sandstone. Sands accumulated
on land by the wind form sand dunes in which the sand
may remain in a loose uncemented condition or under
certain conditions may be more or less perfectly cemented.
The conglomerates are made of the heavier materials such
as pebble and small rock, which is the first to drop out of
suspension in running water. The clays likewise are in
some instances mechanically accumulated, although many
of the clays are residual, having formed in place from the
decay of such clay-bearing minerals as the feldspars.
The clays and shales consist of a mixture of several
mineral, among which hydrated aluminum silicates pre-
dominate. With these is found, in varying quantities,
quartz, mica and other minerals. Sandstones consist
largely of quartz sands, while the conglomerates may be
of any material, although flint pebbles usually predomi-
nate.











The limestones in the secondary formations are either
of chemical or organic-chemical origin. The bases, calcium
and magnesium, are taken into solution and carried by
running water to the lakes and the ocean. Subsequently
under certain conditions they may be precipitated from
the water to form limestone, thus constituting the chem-
ically formed limestones. More frequently, however, or-
ganic processes are involved, the constituents being taken
from the water through the agency of organisms, chiefly
shells and corals, which have the power of extracting
from solution the materials from which the calcareous
skeleton is built. After the death of the animal the skele-
ton remains to form the limestone. Shells accumulate in
this way to form shell limestones, and corals in some
instances accumulate to form a coral limestone. The
foraminifera, animals having a minute calcareous shell,
accumulate in such abundance as to make up extensive
limestones, the formation known as the Ocala Limestone,
underlying Florida, being composed in places chiefly of
these small shells. The oolitic limestones such as the
Miami Oolite in southern Florida are probably in part at
least chemically formed, although many shells and some
corals are included.
The term marl is somewhat loosely applied to calcareous
formations, several varieties of which are found in Florida.
When consisting largely of shells these marls are known
as shell marls. Some of the marls which accumulated in
bogs contain few or no shells, having been apparently
chemically formed.
Some of the other secondary rocks are purely of chem-
ical origin. Among these may be mentioned the bog iron
ore frequently found in old swamps. The iron in these
deposits has been brougrt into the swamps in solution
and subsequently precipitated owing to the organic acids
present in swamp water. The flint masses found fre-
quently in limestone formations are due to segregation of
silica through chemical action.











Owing to the assorting processes which accompany the
formation of the secondary or sedimentary rocks, they
are, as previously stated, much less complex chemically
than are the igneous rocks. This absence of chemical
complexity has an important bearing on the formation of
soil, and there are well-marked differences to be noted,
between soils derived from igneous and those derived from
sedimentary rocks.
It is to be noted in this connection that the formations
found in Florida from which the soils are derived are not
igneous, but are of sedimentary origin. Since there are
many different kinds of sedimentary rocks the soils from
them are necessarily varied. Moreover, the character of
the soil is determined not alone by the formation from
which derived, but also by the climatic, drainage and other
conditions to which it has been subjected. Distinct forma-
tions if similar in character may give rise to similar soils.
Conversely, a single formation under varying conditions
may give rise to various soils, the differences in the soils
being due to the different topographic and drainage condi-
tions under which they have accumulated.

DISINTEGRATION OF ROCKS.

This discussion of soils would be incomplete without
at least a brief mention of the agencies that bring about
the disintegration of rocks. Active among the agencies
of decay are: Changes of temperature; frost or freezing;
wind; water; animals; and plants. Through the con-
tinued activity of these agencies, solid rocks crumble to
dust, the residue forming the mineral constituents of soils.
The combined effect of all these agencies is known as
weathering, and all rocks when exposed at the earth's
surface are subjected to this process.
changes s of Temperature:-Changes of temperature of
rocks result in alternate contraction and expansion, thus
widening existing breaks and joints, loosening the rocks











and permitting the entrance of water, which finds its
way more readily through the rock. In dry climates rocks
heated to a high temperature during the day cool rapidly
at night. Under the influence of heat rocks expand, and
the sudden cooling and contraction of the exterior crust
upon the still heated and hence expanded interior sets up
strains which frequently disrupt and break the crust.
Then, too, rocks consist usually not of one but of several
minerals, and each mineral has its own coefficient of ex-
pansion and contraction and hence contracts and expands
when heated, at a slightly different rate from the asso-
ciated minerals. Thus the different parts of the rocks are
subject to strains, which loosen the minerals and let water
enter more freely, thus hastening decay.

Frost and Freezing:-Aside from the ordinary changes
of temperature freezing in the colder latitudes is an active
destructive agent. When water freezes it expands with
almost irresistible force. The breaks, crevices and pores
of rocks are filled with water as a rule, and when this
freezes, the force of the expansion of the water enlarges
all such openings, thus hastening the decay of the rock.
Decay from freezing takes place most rapidly, as will be
apparent, at seasons of the year when alternate freezing
and thawing occur frequently, as when the surface rocks
thaw during the day and freeze at night. Owing to the
mild climate this factor in the decay of rocks is of minor
importance in Florida.

Wind:-The wind as a weathering agent might, at first
thought, seem to be of little or no importance, yet under
favorable conditions the sand, fine gravel and other ma-
terials, carried by the wind may be hurled with consider-
able force against the face of exposed rocks and thus
gradually wear them away. The wind is most active as an
agent of decay in the deserts and other sections of light
rainfall. Under the action of the wind the softer ma-
terials wear away first. Also, since heavier materials










carried by the wind are carried close to the ground, the
base of exposed rocks is worn more rapidly than other
parts, resulting in fantastic sculpture as seen in some of
the desert rocks.
Water:-The agencies mentioned, changes of tempera-
ture, frost, and wind all exert a purely mechanical effect
in the disintegration of rocks. Water, however, in its
phases of activity, acts both mechanically and chemically.
Falling as rain, water has but feeble mechanical effect,
although in the form of running water a greater mechan-
ical action is exerted, not by the force of water alone,
but more particularly by the force of the impact of ma-
terials thrown by the current against the face of exposed
rocks along the bottom and the sides of the stream. The
mechanical action of water is in this respect analagous
to that of the wind. The waves of the sea and of the
large lakes carry on mechanical erosion by the force of
impact of the waves beating on the shore.
The chemical action of the water is vastly more
effective in the disintegration of rocks than the mechan-
ical. Rocks consist ordinarily, as previously stated, of a
mixture of minerals, and while all minerals are to some
extent soluble, some are much more readily soluble than
others. When these soluble minerals are removed in solu-
tion, the rock necessarily crumbles. Rain water upon pass-
ing through the atmosphere and entering the earth, takes
into solution more or less of the gases, carbon dioxide
into oxygen. From the decaying vegetation in the earth
it receives also various organic acids, all of which ma-
terially increase its solvent action. For this reason many
rocks that are little affected by solution above ground are
disintegrated beneath the surface.
Some chemical reactions in which water takes no actual
part nevertheless take place much more readily in the
presence of moisture. This is particularly true in the
process known as oxidation which is a very important fac-










tor in the disintegration of rocks. This reaction, as pre-
viously stated, takes place much more readily in the pres-
ence of moisture and slowly or not at all in the absence of
moisture. The effect of oxidation is the formation of new
minerals. Oxidation does not necessarily bring about de-
cay, since the oxidized form of minerals is more stable
than most other forms. Indirectly, however, it results
in the breaking up of rocks. If, for instance, rocks ex-
posed at the surface contain sulphides, these on exposure
are likely to be oxidized to oxides and the solidarity of
the rock destroyed.
Hydration is also an important chemical reaction ac-
companying decay of rocks. Hydration is the chemical
reaction by which water is taken into chemical union by
the mineral, thus forming in reality a new mineral. When
hydrated a mineral is found to occupy more space than
in the non-hydrated condition. Not all the minerals in
a rock as a rule are subject to hydration, but the increased
space occupied by the hydrated minerals results in the
disintegration of the rock.
The destructive force of water in the form of ice sheets,
although not effective in Florida, has been of importance
in glaciated regions. Glaciers now exist both in the arctic
and antarctic regions, and in former times they were of
greater extent. During the glacial period immense sheets
of ice moved southward extending, in the central part
of the United States, as far south as the Ohio Valley.
The action of glaciers is characteristic. The ice sheet
moving slowly holds the smaller rocks firmly and pushes
them slowly over the stationery underlying rocks, grind-
ing the rocks to a fine powder, which subsequently reac-
cumulates as soil materials. The glacial soil is often
rich, consisting as it does of rocks thus artificially ground,
having been less affected by the dissolving and assorting
power of water than other soils.
Plants ail .-1 intals :-Thle action of plants and animals










in the disintegration of rocks and the formation of soils
is important. The roots of plants penetrate the rock
crevices and as they grow pry apart the rock thus enlarg-
ing the opening. Seeds of plants likewise fall into crevices
and by their growth open wider the natural breaks in the
rock. Moreover, the roots of plants secrete acids which
act as solvents on the rock. Some marine animals bore
into the rocks, while on land many different animals bore
into the soil, thus bringing the deep and less thoroughly
disintegrated soil to the surface, and also permitting the
rainfall and air to have free access to the deeper soils.
In Florida the so-called salamander, a small rodent,
Geomys tuza floridanus, bores extensively in the sandy
soils. This animal, however, is adverse to moist condi-
tions, and inhabits only the sandy well-drained lands.
In the moist low-lands the cray fish are the most con-
spicuous borers, bringing up large amounts of the sub-
soil to the surface. This type of land is familiarly known
as "'crayfish" land. Among the other borers which affect
soils may be mentioned the earthworms, ants and "go-
phers," the last mentioned being a term applied to a
species of land tortoise.

AccuMUTLATION OF DISINTEGRATED MATERIALS.

The material resulting from the disintegration of rocks
may remain in place as formed, or may be transported a
greater or lesser distance. The agencies of transportation
are numerous. The work of boring animals and plants
referred to above assist in the transportation of soils by
loosening the material and bringing it to the surface. The
wind is an agent in transportation, the finer particles
of the soil being freely moved by the wind. The extensive
line of sand dunes bordering the Florida coast are chiefly
wind blown. The valleys and depressions are continuous-
ly receiving small additions of fine sand and dust par-
ticles blown in by 1 he wind. The chief agent of transporta-










tion of soils, however, is water, the amount of soils trans-
ported by water being much greater than that of all other
factors combined.

'INFLUENCE OF DRAINAGE CONDITIONS ON SOILS.

The soils are affected by drainage conditions in various
important ways, to only a few of which it will be possible
to refer in this paper.
Organic Matter:-The organic matter of virgin soil is
controlled to a large extent by drainage, together with
the atmospheric and climatic conditions. Moisture, ow-
ing to the extent to which it retards oxidation, is a great
preservative of organic matter. Muck accumulates only
where the amount of water in or over the soil is sufficient
to retard the decay of the vegetation. On the other hand,
where the drainage is good and the soils exposed to the
direct rays of the sun, the organic matter natural to the
soil oxidizes and largely disappears.
The Color of Soils:-The color of soils, which is an im-
portant guide in soil classification, is dependent upon
chemical reactions which are controlled to a large extent
by the drainage conditions. The chief mineral stain in
soils is iron in its varying forms. Those soils and sub-
soils that are thoroughly saturated with water at all times
are likely to be dark or drab in color. The dark color
is due to the fact that the iron is in an unoxidized or de-
oxidized condition. When partly, although imperfectly
drained, soils assume a mottled appearance, the mottling
being due to the partial oxidation of the iron. The bright
red soils are those in which the iron has been thorough-
ly oxidized and exists in the non-hydrated form, hema-
tite. The ochre yellow soils are believed to be stained
in most cases by the hydrated iron oxide. Those soils
which lie on the slopes and are well drained and are rap-
idly, renewed by the addition of soil material from be-










neath are most frequently red in color. On the other
hand, the ochre yellow soils are found in areas where both
drainage and aeration are good, but where the conditions
are such that there is little or no surface wash, and
where consequently the renewal of soil is slow. It is
probably true that red soils when long exposed to the air
and to moisture such as is afforded by capillary move-
ment, change over to yellow soils, the change in color be-
ing due to the hydration of the iron oxide.

The Water Table:-By the term water table is meant
the level at which water stands in the soils. Above this
level, while the soils may be and usually are moist, the
moisture is that due to capillary movement of water and
the soils are aerated. At and below this level the soils
are saturated and the air is practically excluded. The
physical and chemical conditions above and below the
water line are consequently in marked contrast. Above
the line the oxidizing processes prevail, below the line the
de-oxidizing processes prevail. The minerals above the
water line tend to assume the form of oxides; while below
the water line the minerals more frequently exist as
sulphides or sulphates. Above the water line the move-
ment of water following heavy rains is free and solution
is active; below the water line the movement of water
is sluggish and limited and deposition instead of solution
may occur.

Hardpan:-The hardpan of the palmetto flatwoods of
Florida and other coastal plain states affords a striking
illustration .of the relation of the soil conditions to the
water line. The hardpan forms at the average level of
the water table. It consists of a stratum stained dark
or chocolate color by organic matter. During the dry sea-
sons when the water table falls below its average level
the hardpan is firmly cemented, presumably by the coat-
ing of organic matter. In this condition it can scarcely
be penetrated by the soil auger, and interferes with the
2-Class. Soil.










movement of water by capillarity. During the rainy sea-
son when the water table rises above the average level,
the hardpan stratum becomes saturated with water and
tends to disintegrate. Although many details of the for-
mation of hardpan remain to be explained, it is evident
that organic matter from the surface stratum is carried
downward in some form by the water and is reaccumu-
lated in the hardpan stratum.
Translocation of Clay Particles :-Another important
feature of the drainage conditions is the translocation
of clay particles. By this term is meant the removal
of the finely divided clay particles from the soil near the
surface and their reaccumulation at a lower level. This
process is of special importance in Florida. The
soils over large areas in central Florida are derived from
a clayey sand rock. The clay in this formation which
acts chiefly as the cementing material is in a very finely
divided condition. Upon the .disintegration of the for-
mation, the clay particles are loosened, and are car-
ried by the percolating waters to a lower level, and are
there reaccumulated. Under conditions of good surface
drainage and heavy rainfall this process long continued
results in washing the sand free of clay to a consider-
able depth and in the accumulation of an increased
amount of clay in the stratum beneath. The dividing
line between the sand washed free of clay and the strat-
um beneath in which the clay occurs in excess, is often
a well defined line. The clay stratum accumulated in
this way is sometimes referred to as hardpan although
it is totally different in character from the hardpan of
the flatwoods.

PLANT FOOD DERIVED FROM THE SOIL.

Of the eighty or more known chemical elements about
ten are believed to be essential to the growth of plants.
Of these six are derived by the plant wholly and the ser-










enth chiefly from the soil. The others are taken by
Ithe plant either from the atmosphere or from water.
The elements taken entirely from the soil are calcium,
iron, magnesium, phosphorus, potassium and sulphur.
Nitrogen is taken chiefly from the soil, although the
group of plants known as legumes are able to take nitro-
gen from the air. The remaining essential elements, car-
bon, oxygen and hydrogen, are taken directly from the
air and the water, the carbon dioxide gas of the atmos-
phere, and water absorbed through the roots, being the
sources of supply. As regards the amounts of the several
elements the carbon, oxygen and hydrogen taken from the
air and water make up approximately 95 per cent of the
plant structure by weight, the seven elements taken from
the soil combined making up only about 5 per cent by
weight. Although required in such relatively small quan-
tities the elements derived from the soil are none the less
necessary, and if any one of the seven is lacking or defi-
cient or not available, the productiveness of the soil is
thereby reduced.

THE SOILS OF FLORIDA.

In order to understand the soils of Florida it is well
to bear in mind the character of the parent formations
from which they originated, the conditions under which
the soils accumulated, and the climatic conditions to
which they have been subjected since their formation.
A consideration of the character of the formations
from which the soils were derived involves a review of
the early history of Florida. In early geologic time the
land area that we now know as Florida was submerged
and formed at that time a part of the ocean bed. Dur-
ing its period of submergence geologic formations were
accumulating. It was not until the area became dry
land that soils began to form. However, the kind of ma-
terials that accumulated while the area was submerged











determined to a large extent the character of the soils
that were to form after the area became dry land.
It is not difficult to understand the kind of materials
that accumulated in the ocean bed during the period of
submergence, since similar materials are still accumulat-
ing under similar conditions. Sand and shell deposits
are being formed along the shore at present as in the
past. Off the coast near the mouths of large rivers
clays, muds and sands are deposited forming clays, shales
and sandstones. Those who have visited the Florida keys
along the southeast coast from Miami to Key West can-
not fail to have observed that limestone is there rap-
idly forming. The clear waters are favorable to ma-
rine life, including many shells and other forms having
calcareous skeletons. After the death of the animal,
the shell, more or less broken by the waves, falls to the
bottom. Large coral masses are frequently rolled about
in the shallow water on the reefs and more or less com-
pletely ground to pieces. So abundant is the ground up
and fragmental material in these shallow waters that
following a storm the water becomes milky white with
the material in suspension, which again settles to the
bottom when the water becomes quiet.
We are not, however, confined to analogy to determine
the conditions that prevailed while Florida was submerg-
ed. The limestone, sandstone, clay and shell deposits that
were formed during that time tell their own story of the
conditions under which they were deposited.
The .oldest of the formations that we now find ex-
posed at the surface in Florida is an extensive limestone
known as the Ocala Limestone. This formation under-
lies all of Florida and parts of the adjoining states.
In central and northern Florida it is frequently exposed
at the surface, and hence affects the soils. In eastern
and southern Florida it lies buried beneath later for-
mations to such a depth as to have no appreciable ef-











fect on soils. The conditions which prevailed while this
limestone was being formed, as shown by the rock it-
self, were as follows: A clear sea of medium depth,
free, or nearly so, from land sediment. In this sea ma-
rine life abounded. Minute organisms known as foramini-
fera were particularly abundant, the shells of these small
animals making up the greater part of the deposit.

Along with these minute shells are larger shells, some
corals, sea urchins and various other animals. That
these conditions prevailed through a long period of time
is evident from the fact that limestone accumulated
to a thickness of several hundred feet.

Masses and layers of flint are now frequently found
in this formation, but these have been subsequently formed
by replacement of calcium carbonate by silica carried
in solution by water which circulates freely through the
limestone. Locally also the limestone has become com-
pact and close grained. This change also is to be at-
tributed to solution and deposition by the underground
waters.

The localities where the Ocala limestone is exposed
at the surface in north central Florida are numerous. It
is found in the sinks on the University grounds near
Gainesville; in Alachua sink at the edge of Payne's prai-
rie; in practically all of the phosphate pits in Alachua,
Columbia, Suwannee, Marion, Levy, Citrus and Hernando
Counties. In western Florida it is exposed in Jackson
and Washington counties. When at or near the surface
this formation has an important influence on the forma-
tion of soils.

After the Ocala Limestone was formed in the Flor-
ida ocean the conditions changed somewhat, and an in-
creased amount of sediment was washed in from the
land. This in turn caused the marine life in the ocean
to become less abundant. The deposits that were ac-










cumulated include impure or clayey limestones, and later
when the amount of wash from the land had further in-
creased calcareous clays and sandstones were formed .The
deposits that were formed under these changed condi-
tions are known as the Apalachicola group of forma-
tions. They overlie the Ocala Limestone along the Apa-
lachicola River in western Florida and along the Gulf
coast in southern Florida.

It is evident that during these changes of conditions the
Florida sea was becoming more shallow, and that the
deposits that formed were more local in character. As
the waters became more shallow the conditions were favor-
able locally for the development of shell marls. Such
marl deposits are found in various parts of the State.

In late geological time there was formed the extensive
limestones that border the coast from St. Augustine to
Key West and underlie likewise the Everglades and the
extreme south end of the peninsula. These limestones vary
in character. Along the Atlantic coast from St. Augus-
tine to Brevard County shell rock, known as coquina, pre-
dominates. At Miami and at Key West the limestone is
oolitic in character. Along the keys from Key Largo
to Knights Key coraline rock is found, the only true cora-
line limestone in Florida.

In passing thus hastily over the formations that suc-
ceeded the Ocala Limestone, it is not intended to im-
ply that these are not of importance in the problems of
soil formation. On the contrary, they are very impor-
tant, but these later formations are more or less local
in character, and it is scarcely possible to give at this
time a detailed description of each. In the publica-
tions of the State Geological Survey, particularly in the
Fourth Annual Report, 1912, will be found a fuller ac-
count of these deposits in their relation to the formation
of soils.










Conditions Under Which the Soils Accumulated:-
Soils are materially affected by the conditions under
which they accumulate, and a single formation may
give rise under varying conditions to radically different
soils. The influence of drainage on the amount of or-
ganic matter, color, physical character and fertility of
soil has already been discussed. The hardpan, a spe-
cial feature arising from the drainage conditions was
also described. The bright red soils and ochre yellow
soils are records of varying stages of chemical action con-
trolled by the condition under which the soils are formed.
Some large areas in Florida are particularly well drained,
so much so that almost no surface water is to be found.
Other areas are poorly drained, affording conditions fa-
vorable for the accumulation of dark colored or muck
soils. The great diversity in the drainage and other condi-
tions in Florida, as well as variation in the parent for-
mations, has resulted in a wide variation in the soils
found in the State.

Climatic Conditi6ns:-The climatic conditions to which
soils have been subjected have an important bearing on
their character. It is well known that the soils of arid
regions differ materially from those of regions of aver-
age or heavy rainfall. In countries where soils are but
little washed by rainfall the soluble constituents accu-
mulate, not infrequently as in the case of alkali lands,
to an extent that is injurious to plants. In regions of
medium and heavy rainfall more or less of the soluble
ingredients are removed from the soils. In fact, fertil-
izers are added to soils to replace constituents that have
been removed in solution by rain water. Thus a heavy
annual rainfall, while it frees the soil from such de-
leterious constituents as alkalies, and supplies the soil
moisture so essential to plant growth, yet takes its toll
in the form of essential plant food dissolved by the rain-
water while passing through the soil.










The amount of rainfall in Florida varies in the dif-
ferent sections of the State, being heaviest in west
Florida and at one or two stations along the east coast,
while Key West in extreme southern Florida is below
normal. The average rainfall for the State as a whole
is about 54 inches per annum.

CLASSIFICATION OF SOILS IN GENERAL.

A satisfactory classification of soils is difficult, and
the subject may be approached from any one of several
different viewpoints. In fact, various classifications have
been proposed to serve various purposes. A common clas-
sification is that in which the soils are classed in ac-
cordance with their manner of formation as residual,
transported, or colluvial.

Residual Soils:-The residual soils in this classifica-
tion are those that have formed in place. Under these
conditions the parent rock from which the soil is de-
rived lies beneath the surface at a variable depth, de-
pending on the duration and intensity of the weathering
processes and upon the surface contour, rainfall, sur-
face wash and other conditions. On the steep slopes little
or no soil accumulates, being removed by surface wash
as rapidly as formed. On the more gentle slopes and
level lands, if the weathering processes have been long
continued, soil may accumulate to a great depth. The
class of residual soils may be sub-divided into those de-
rived from igneous rocks and those derived from sedi-
mentary rocks. Those derived from sedimentary rock
may be .designated as residuo-sedimentary. The soils de-
rived from igneous rocks possess certain distinctive char-
acteristics due to the fact that the parent rocks are
chemically and mineralogically complex, and to the fact
that the soils have in no stage been subjected in any
marked degree to the assorting power of wind or wa-










ter or other agencies. The residuo-sedimentary soils on
the contrary are derived from rocks the materials of which
is a previous stage of disintegration were more or less
perfectly assorted by wind or water or other agencies.
For this reason the sedimentary rocks give rise to soils
less complex mineralogically and probably also less com-
plex chemically than the soils from the igneous rocks.

Transported Soils:-The transported soils are those
that have been moved more or less from the place where
originally formed, and have been redeposited at another
locality. The importance of this process arises from
the fact that in being transported the soil materials are
subjected to more or less assorting. The alluvial soils of
the river valleys represent the finer materials carried by
the water of the river at flood stages. The wind blown
soils are designated as aeolian.

Colluvial Soils:-The colluvial soils are those that have
been but slightly moved from the place where originally
formed. They are found chiefly along hill sides, being due
largely to creep of the soils, or to land slides which carry
the soil materials to a lower level and mix it to a limited
extent with soil materials from other sources. The col-
luvial soils differ from the residual soils in that they have
been somewhat removed from their place of formation.
They differ from transported soils in that they have not
been subjected to the assorting of materials to any appre
ciable extent.

Common Termls Applied to Soils:-Another classifica-
tion of soils in common use is that which refers to the
soil ingredients rather than to the manner of formation.
The clay soils are those in which clay predominates. Sandy
soils are those in which sand is an abundant mineral con-
stituent. Silty soils consist of finer materials, including
fine sand and finely divided clay. Loams are those soils
that have an admixture of sand and clay. Other terms, as











:alcareous, furruginous and muck soils, are self-explanai
liry. The clay soils are often referred to as heavy, and
the sandy soils and loams as light, referring to the ease
with which they may be cultivated. The heavy soils, al-
though more difficult to farm, are frequently very durable
owing to their clay ingredients, the decomposition of the
clay minerals supplying plant food.

Specific and Technical Soil Names:-For convenience
of description and reference in detailed soil surveying
and mapping specific names are applied to soils. The
most extensive system of soil nomenclature now in use is
that established and followed by the Bureau of Soils of
the United States Department of Agriculture. Accord-
ing to this system, the whole territory of the United States
is divided into thirteen hysiographic divisions or soil
provinces. The soils in each province are grouped in cer-
tain main divisions designated as soil series. Each series
in turn includes one or more soil types. The soil series is
defined as including soils that are alike in origin, color
and in some physical properties. The soil type, or soil
name, is a more definite unit than soil series, and applies
to a particular kind of soil within the series. The soil
name is formed by adding to the name of the series a
term descriptive of the soil. Thus the Norfolk sand re-
fers to a soil in the Norfolk series in which both soil and
sub-soil are sand. Similarly, Portsmouth sand refers to
a soil of the Portsmouth series having a sandy top soil
and sub-soil. The texture of the soil may be further in-
dicated by introducing a descriptive term such as coarse
sand, fine sand, or very fine sand. In describing soils
the depth of three feet is taken as a standard, and if
a clay sub-soil is found within this depth the soil is
termed a loam. Norfolk sandy loam thus means a sandy
top soil and a clay sub-soil within a depth of three feet
or less. Portsmouth sandy loam, or fine sandy loam, re-
fers to soils of the Portsmouth series having a clay sub:










soil within three feet of the surface. While the introduc-
tion of specific soil names is desirable in detailed soil sur-
veys: it will not be necessary to use these terms in the
general discussion of the Florida soils which follows.

CLASSIFICATION OF THE SOILS OF FLORIDA.

The soils of Florida are extremely varied, yet for the
purposes of a general survey, representative types of coun-
try may be recognized in which particular soils predomi-
nate. The classification that is here proposed is based
upon the character of the soil and sub-soil, the amount
of organic matter in the soil, the drainage, the native
vegetation, and upon such other conditions as may be
readily determined. The terms used are descriptive, and
are not intended as technical names of soils. The use
of technical terms has been intentionally omitted from
this paper.

PINE LANDS.

About 70 or 75 per cent of the total land area of Florida
was covered originally by pine forests. In northern cen-
tral and western Florida the long leaf, or yellow pine.
Pinus palustris, is the prevailing forest tree, while in
southern Florida the Cuban pine, Pinus caribaea, predom-
nates. The short leaf pine, Pinus echinate, grows in the
hammock type of country in association with deciduous
trees. The same is true of the spruce pine, Pinus clausa,
which grows extensively on quiescent dunes, bordering the
coast. A few other pine species are found, but they
occupy less extensive areas. The pine lands are varied,
and several more or less distinct types may be recognized.
Rolling, Upland or Well-Drained Pine Lands:-The
rolling pine lands include well-drained areas, also known
as high or upland pine. This is an extensive type of
country, and is itself varied in soils and topography. The










prevailing forest tree is the long leaf-pine. As a rule
there is little or no undergrowth, although in the more
sandy localities small oaks are found. Saw palmetto oc-
curs rarely and only to a limited extent.
The top soil in the rolling pine lands is light colored


or gray, or dark from the admixture of organic matter.
The depth to the clay is variable, and several grades of
soil in this type of country are recognized, depending
chiefly upon the texture of the soil drainage conditions
and the character of the sub-soil. In some sections the










underlying sandy clay is found at a depth of one to two
feet. In these areas if well drained the clay usually con-
tains iron pebbles and is oxidized red in color. Else-
where the clay lies from three to six or more feet beneath
the surface and in the extremely sandy soils the clay
lies at an even greater depth.

Some of the very desirable general farming lands are
found in the belt of rolling pine land. This is true in par-
ticular of those soils having clay sub-soil within a few
feet of the surface. Other sandy soils in which the clay
is not within a determinable depth are less productive,
although even these more sandy soils under proper culti-
vation are made to yield satisfactory returns. In the
heavier types of soils having a clay subsoil near the sur-
face the pine when removed will reforest itself naturally
but on the very sandy soils the pine when cut off is quick-
ly replaced by a dense growth of scrub oaks.

The rolling pine lands are too extensive to call for
specific reference to areas. The interior of the State is
chiefly of this type. A large number of soil types are
included which can be properly separated and mapped
only by detailed surveys. The pine lands in the limestone
sections of the State present many differences in topo-
graphy, in drainage and in grade of soils, from the pine
lands in the non-limestone sections.

The following is an analysis of a sample of the well-
drained pine land of Osceola County. The principal vege-
tation is pine and scattered oak, and wire-grass. The
sample was collected by R. E. Rose. The analysis is taken
from Bulletin 43 of the State Experiment Station.












Analysis of Virgin High or Rolling Pine Soil and Sub-soil.'

Soil. Sub-soil.

Coarse earth .................. .90 .20
Fine earth .................... 99.10 99.80
Humus ........................ .38 .97
Nitrogen ............... ...... .0350 .0182
Moisture ...................... .1860 .3300

Analysis of the Fine Earth:

Insoluble residue .............. 97.2280 97.7060
Potash (K.O) .................. .0077 Trace
Soda (NA 0O) .................. .0067 .0278
Lime (CaO) ................... .0225 .0000
Magnesia (MgO) .............. .0144 .0063
Ferric Oxide (Fe,O,) 1.937
Alumina (A103)) ............... .0718 .2183
Pnosphorus pentoxide (POs).... .0032 .0080
Chlorin ........................ Trace Trace
Sulphur trioxide (SO3) ......... .0060 Trace
Carbon dioxide (CO,) ......... .0000 .0000
Water and organic matter...... 2.7980 1.9500

Total .....................100.1583 100.1101

The following analysis is also taken from Bulletin 43 of
the State Experiment Station. This sample was collected
by C. W. Wilson and was taken from near Lake Elbert, in
Polk County. The principal growth upon the land is
small pine, with more or less oak. The sample represents
the sandy rolling lands of the lake region:

Analysis of Virgin Rolling Pine Land, Soil and Sub-soil, of the
Lake Region.

Soil. Sub-soil.

Coarse earth ................ 8.83 7.16
Fine earta ................... 91.17 92.84
Hum us ........................ .54 .17
Nitrogen ...................... .0182 .0014
Moisture .................... .1800 .1000
Analysis of the Fine Earth:











Analysis of Virgin Rolling Pine Land, Soil and Sub-soil, of the
Lake Region-Continued.
Soil. Sub-soil.

Insoluble residue .............. 97.4560 98.3770
Potash (K,0) .................. Trace Trace
Soda (Na2O) .................. .0234 .0344
Lime (CaO) ................... .012o .0000
Magnesia (MgO) .............. .0261 .0117
Ferric Oxide (Fe.O,) .3487
Alumina (ALO,0 ) ............... .4678 .1912
Phophorus pentoxide (P2O,).... .0272 .0176
Cnlorin ........................ Trace Trace
Sulphur trioxide (SO,).......... Trace .0000
Carbon dioxide CO,) ........... .0000 .0000
Water and organic matter...... 2.0140 1.0194

Total .................... .100.0270 100.0000

FLATWOODS.

The term "flatwoods" is applied to pine lands which
are more level and consequently less well drained than
the rolling pine lands.

Palmetto Flatwoods:-A widely prevailing type of
country in parts of peninsular and west Florida is that
which may be designated from its characteristic vegeta-
tion as palmetto flatwoods. The native timber growth
is pine of several species, among which the long leaf, or
yellow pine, Pinus paIustris, predominates, although in
extreme southern Florida the species is replaced by the
Cuban pine, Pinus caribaea. The characteristic under-
growth is wire grass and the saw palmetto (Serenoa ser-
rulata). The palmetto flatwoods are in general level and
sometimes so flat as to be more or less flooded during the
rainy season. These overflows, however, are temporary,
as the palmetto will not withstand excessive or prolonged
flooding. The smaller streams are bordered by more or
less swamp of hardwood growth. The larger streams, as.











a rule, are confined to definite channels in the palmetto
flatwoods, have sandy banks and are not bordered by
swamps other than the alluvial swamps of the rivers.
Small circular depressions occupied by swamps of cypress
or of hard wood trees are frequent in the palmetto flat-
woods.

The soil is sandy and usually contains sufficient organic
matter to give a gray or dark color. The palmetto flat-
woods is very generally underlaid by a dark or chocolate-
colored stratum known as" hardpan. The dark color is
chiefly due, in the samples which have been analyzed, to
organic matter. The coloring is most intense in the up-
per part of the stratum. After passing one to three inches
into the stratum the color grades to a chocolate or coffee
grounds color, which in turn gives place at a variable
depth to light-colored sand. The pine trees on saw pal-
metto land rarely grow as large as on the other pine lands.
The tap root upon reaching the hardpan stratum usually
curls up or flattens out. The hardpan is the most char-
acteristic and persistent feature of the palmetto flatwoods.
Hardpan in the palmetto flatwoods is frequently found at
a depth of 18 to 30 inches, although it may lie deeper, its
occurrence and depth and thickness being controlled by
the drainage conditions. During the dry season the hard-
pan becomes indurated, and is said to interfere with the
return of water to the surface by capillarity. In the
case of irrigated lands this objection is overcome, and it
is a notable fact that some very successful trucking land,
of the State are irrigated lands .of this type, having, how-
ever, a clay sub-stratum beneath the hardpan. The fol-
lowing analysis is of a sample of hardpan.

Analysis of a sample of hardpan from palmetto flat-
wods; sample collected by R. M. Harper; analysis by A.
M. Henry, Assistant State Chemist:











Per Cent.
Silica .............................. ... .......... 95.62
Volatile or combustible matter .................. 3.33
Undetermined (mostly clay) ..................... 1.05

T otal ................................ .......100.00


The most extensive areas of palmetto flatwoods lie bor-
dering, or at least near, the coast. It is not, however,
confined entirely to the coast, but occurs inland where
conditions are favorable. Local areas of palmetto flat-
woods are found interspersed with other types of soil
3-Class. Soil.









34

through the greater part of peninsular Florida, except in
the limestone section east of the Everglades in southern
Florida, where a distinct type of palmetto pine land is
found. West of the Apalachicola River, aside from the
strip bordering the Gulf coast, the palmetto flatwoods are
not extensively developed.

Following is the analysis of a typical sample of the soil
and sub-soil of the palmetto flatwoods taken by R. E.
Rose in Osceola County. The chief vegetation growing
upon the soil is pine, saw palmetto and wire grass. The
analysis is from Bulletin 43 of the State Experiment Sta-
tion, page 666.

Analysis of Virgin Soil from Palmetto Flatwoods.

Soil. Sub-soil
Coarse earth .................. 1.10 .40
Fine earth .................... 98.90 99.60
H um us ........................ 1.02 .38
Nitrogen ...................... .0490 .0014
Moisture ...................... .3800 .1500

Analysis of the Fine Earth:

Insoluble residue .............. 96.6970 98.7755
Potash (KO) .................. .0073 Trace
Soda (NaO) .................. .0438 .0172
Lime (CaO) ................... .0150 .0000
Magnesia (MgO) .............. .0252 .0054
Ferric Oxide (FeO,) .2712
Alumina (ALO1 ) ................ .0854 .1733
Phosphorus pentoxide (P,05) .... .0096 .0080
Chlorin ....................... Trace Trace
Sulphur trioxide (SO,) ......... Trace .0042
Carbon dioxide (CO,) .......... .0000 .0000
Water and organic matter ...... 3.1167 .8620

Total .....................100.0000 100.1168
The following is the analysis of a sample of the pal-
metto flatwoods near Punta Gorda in DeSoto County.
From Bulletin 68 of the State Experiment Station, by












H. K. Miller and H. H. Hume. The chief vegetation is
Cuban pine and saw palmetto.

Analysis of Sample of Virgin Flatwoods.
Soil. Sub-soil.
Insoluble matter ............... 98.9060 99.4696
Soluble silica .................. .0120 .0195
Lime .......................... .0475 .0300
Magnesia ..................... .0144 .0099
Potash ........................ .0110 .0061
Iron and alumina ............. .0725 .0407
Phosphoric acid ............... .0050 .0068
Sulphur trioxide ............... .0068 .0051
Volatile matter ................. .9852 .4480
Humus ........................ .4981 .2550
Nitrogen ...................... .0250 .0090

Mechanical analysis of same, made by the Bureau of Soils, of
the United States Department of Agriculture.

ISoil. Sub-soil.
Organic matter ........ 1.16 per cent .58 per cent
Gravel, 1 to 1 mm....... .14 Trace
Coarse sand, 1 to 5..... 2.84 2.00
Medium sand, .5 to .25.. 6.72 6.02
Fine sand, .25 to .1 mm.73.50 75.02
Very fine sand, .1 to
.05 mm .............15.00 15.84
Silt, .05 to .005 mm.... 0.56 .32
Clay, .005 to .0001 mm.. 1.12 .30

Open Flatwoods:-Another extensive type of country
is that which may be designated as the open flatwoods
or pine meadows. This type of country has practically
no undergrowth other than the heavy mat of grass, chief-
ly wire-grass. The forest growth is chiefly the long leaf
pine and slash pine. The streams through this type of
country are flat bottomed and bordered by a dense swamp
growth of hard wood trees of various kinds. The land
is very level, so much so that drainage is imperfect and
the land is more or less flooded during the summer rainy











season. Ditching is necessary in order to drain the land
for farming. The long leaf pine when cut off of this type
of land reforests itself. The top soil is colored dark by
the presence of organic matter, A few inches beneath


1
1 .:L_~ -

1~E~c;
11~
'


the surface the soil becomes dark gray. A clay sub-soil
may or may not be present and several varieties of soil
may be distinguished, depending upon the texture, the
sub-soil and the drainage conditions. Hardpan is not as-
sociated with this type of soil.










Large areas of soil of this type occur in both east and
west Florida. In Nassau County a large area lying
between the Seaboard Air Line Railway on the east and
the Atlantic Coast Line Railroad on the west, reaching
to the St. Marys River, is of this type. In Duval County
a considerable area of this class surrounds Baldwin near
the west line of the county. Along the St. Johns River
areas of this type of soil occur at several places. In west
Florida areas of this type are extensively developed.
When cleared and sufficiently drained this type makes
desirable farming and trucking lands.

Much of the lands of the Florida flatwoods can be made
available for farming by shallow ditching such as each
farmer may make for himself at a nominal expense. How-
ever, there are large areas that would be benefited by
more extensive systems of drainage. Such operations are
being carried on in different parts of the State either by
communities or by private parties.

PINE LANDS OF THE MIAMI LIMESTONE.

A considerable area of country lying along the eastern
border of the Everglades and extending from the Ever-
glades to the Atlantic Ocean is underlaid by limestone
and supports a characteristic growth of Cuban pine and
saw palmetto. The limestone is oolitic in character and
lies very near the surface, being frequently exposed or
covered oniy by a thin mantle of loose light colored sand.
The roots of the pine being unable to penetrate the rock,
spread out horizontally along the surface, -the pine on
this land having no distinct tap root. Although the soil
covering overlying the limestone is of no great thickness,
owing probably to the relatively short time, geologically,
that the surface has been exposed to the soil-forming
processes, yet for fruit growing and trucking purposes
this limestone soil has long since proved its value.









38


The following analysis of samples of virgin rock soil
from the Biscayne Bay, in Dade County, were made by A.
A. Persons, and are published in Bulletin 43 of the Florida
Experiment Station, pp. 653-655. The analyses were made
in accordance with the methods adopted by the Associa-
tion of Official Agricultural Chemists in 1895:

Analysis of Virgin Rocky Soil from Biscayne Bay.


No.
Surface.
Coarse earth ............. 7.20
Fine earth ............... 92.80
Hum us ................... 2.77
Nitrogen ................. .1666
Moisture at 100 C......... 1.2160
Analysis of the Fine Earth.
Insoluble residue .......... 87.7215
Potash (K..O) ............ .0043
Soda (NaO) ............. .0812
Lime (CaO) .............. .1275
Magnesia (MgO) ......... .0612
Ferric oxide (Fe,O,)....... .0278
Alumina (A102) ......... .0682
Phosphorus Pentoxide (P20,) .0240
Chlorin ................... Trace
Sulphur trioxide (SO,).... .0103
Carbon dioxide (CO,) .... .0000
Water and organic matter. 11.4600

Total ................ 99.5860


1.
Sub-soil.
7.40
92.00
.10
.000
.0380

99.0850
.0024
.0748
.0425
.0108
.0914
.0162
.0224
Trace
.0086
.000
.6620


No. 2.
Soil. Sub-soil.
2.60 7.00
97.40 93.00
.23 .21
.0182 .0042
.1660 .1720


98 0255
.0178
.0804
.0725
.0351

.2044
.0256
Trace
.0086
.0000
1.5301


96.5225
Trace
.1046
Trace
.0387
.6519
1.0363
.0268
.0483
.0103
.0000
1.5606


100.0161 100.0000 100.0000


HAMMOCK LANDS.


The term hammock is applied to lands having a heavy
growth of trees or shrubs among which usually the decid-
uous or hard-wood trees predominate. The hammocks in-
clude several distinct types of soil, and although not
extensive in area, are important agriculturally.
Calcareous Hammock:-The calcareous hammock lands
are underlaid at a depth not exceeding a few feet by some
form of calcareous deposits, as marl, limestone, shell
rock or shells. The native vegetation in the calcareous
hammocks includes usually a variety of plants adapted











to a calcareous soil. Among these are many hard-wood
trees and shrubs, and where sufficiently moist the cabbage
palmetto. The limestone, marl or shell, as the case may
be, often lies practically at the surface or is covered by





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only a thin layer of soil. Such soils are fertile and last-
ing, and are well adapted to trucking crops.
Some extensive hammocks underlaid by limestone are
found along the Gulf coast in Hernando, Citrus, Levy,
Lafayette, Taylor, Jefferson and Wakulla counties. The
hammocks in Wakulla and Jefferson counties are under-











laid by the Chattahoochee limestone. The more exten-
sive hammocks of Levy, Citrus, and Hernando counties
are underlaid by the Ocala Limestone. Hammocks rest-
ing upon the Ocala are found in the interior of the State
in Alachua, Marion and Sumter counties.

An extensive line of carlcareous hammock land under-
laid chiefly by shell marl and shell rock is found border-
ing the Atlantic coast almost continuously for a distance
of about 150 miles. This east coast hammock rests chiefly
upon and is caused by the coquina shell rock and marl.
In the vicinity of Ormond, Daytona and New Smyrna this
hammock belt reaches a width of from one to three miles.
Another considerable development of the hammock is
found a short distance north of Titusville. In these
localities the hammock is known as Turnbull's hammock,
being a part of the Turnbull grant made during the days
of English rule. At Rockledge is seen another excellent
development of the hammock belt immediately border-
ing the coast.
The Caloosahatchee River and some of its tributaries
is bordered by calcareous hammock land, the formation
giving rise to the hammock being the Caloosahatchee marl
of Pliocene age. Many smaller calcareous hammocks oc-
cur throughout the State.
Clay Hammock Lands:-Another distinctive type of
hammock land is that which may be designated as the
clay hammock lands, a clay sub-soil being frequently
present. This type is due to the topography and is found
only in rolling, well-drained or somewhat hilly sections,
where the slope is sufficient to permit a partial removal of
surface sands, thus permitting the addition of new soil
from the underlying clays. The result is a strong and
well-drained soil. The native vegetation includes hard
wood trees of several varieties, among which are oak and
hickory; the short leaf pine is also frequently found on
this type of soil.










The largest areas of this type are the hammock lands
of Leon, Jefferson, Madison and Jackson counties.
Holmes valley in Washington County, and Euchee valley
in Walton County represent a similar hammock type due
to similar causes. The Holmes valley hammock lies along
the border line between the lowlands of Holmes Creek
and the elevated sandy plateau of the interior of the
county. The surface wash along the foothills of this
plateau is sufficient to remove the surface sand and to
expose in places the underlying sandy clay, giving rise
to a rolling hammock land with the usual hard wood and
short leaf pine vegetation. Euchee valley represents the
foothills encountered in passing from the lowlands of the
Choctawhatchee River to the uplands of the interior of
Walton County.

SAND HILLS.

This type of country is rolling and' distinctly sandy.
The native growth is a sparse scattering of pine and a
dense growth of scrub oak. There is a limited amount
of organic matter in the soil, and the top soil may be
bleached light colored, although a few inches beneath the
surface the soil is usually light yellow in color. Although
there are no surface streams the drainage of the sandhill
country is good, as the rainfall passes at once into the
sand. Hordpan was found in the sandhills at a depth of
from twenty to twenty-five feet, this depth representing
the water level at that particular locality.

THE SAND DUNES.

The sand dunes, recent and ancient, form by no means
an unimportant type of country. These are found chiefly
bordering the coast. Along the Atlantic coast sand dunes
are found extensively. Near the north line of the State
at Fernandina the dunes border the coast, and are form-










ing at present. Passing south, a line of ancient and
quiescent dunes borders the coast lying from one-half
to one and two miles inland, for a distance of 200 miles.
When formed these dunes probably faced the coast, the
land lying then at a lower level than at present. A sub-
sequent slight elevation of the land having extended the
coast line a short distance beyond the dunes. Since the
elevation, which occurred probably at the close of the
Pleistocene time, these dunes have become quiescent and
are now overgrown by the dense growth of vegetation,
consisting of spruce pine and shrubby plants. At the
extreme southern end of the State recent calcareous sand
dunes occur. Along the Gulf coast of Florida low quies-
cent sand dunes are found bordering the coast in Lee,
DeSoto, and Manatee counties. From. St. Petersburg
along the Gulf coast to Wakulla County the dunes are
lacking. This coast is chiefly calcareous, representing
that part of the coast line in which the Oligocene lime-
stones border the coast. The western part of the Gulf
coast from Franklin to Escambia county is a section from
which limestones-are absent and sandy clay formations
are exposed. Along this coast the sand dunes are again
found more or less continuously. Those of the mainland
are mostly quiescent. When originally accumulated the
sand of the dunes was probably homogeneous or nearly
so. Subsequently under the weathering process a clear
line of demarcation has been established between a top
layer one to four feet in thickness and that which lies
below. The top layer of sand is light colored or slightly
gray near the surface from the accumulation of organic
matter. At a depth of from one to four feet the color
changes abruptly to a pale yellow. This line of demarca-
tion follows the contour of the hill in a cross section of
the dune. On the east border of Lake Kingsley in Clay
County is found a series of dunes made up of white and
unusually well-washed sands.
The sand dune land of southern Florida has been found











to be particularly well adapted to the growing of pine
apples.
SCRUBS.

The native vegetation of the "scrub" is more or less
dense, and is often an almost impenetrable growth of
shrubs or stunted trees of various kinds. The top soil is
frequently light colored, although where the vegetation
is dense, some organic matter accumulates. Passing be-
neath the surface the soil as a rule becomes ochre yel-
low.

Somewhat extensive areas of scrub lands are found in
central peninsular Florida. It is frequently associated
with, but not confined to, the lake region type of topog-
raphy. The scrub is well drained, since the rainfall
passes at once into the sand. Sandy pine lands frequently
give place to scrub without any apparent change in soil,
topography or drainage conditions.
The present vegetation of the scrub has probably re-
placed an earlier growth of pine. This process .of replace-
ment of pine forests by the sand-loving species may be
observed in many localities. The deciduous oaks are first
to obtain a foothold among the pines. These in turn give
place to the evergreen oaks, which predominate in the
scrub.
PRAIRIE AND SAVANNA.

The terms prairie and savanna are applied to lands
that are level and devoid of trees or nearly so. The
prairies as a rule are better drained than savannas, al-
though many of the prairies that are entirely dry during
the dry season are more or less flooded during the season
of summer rains. The soil of the different prairies is so
variable as scarcely to admit of a generalized description.
Clay soils and sandy soils are included as well as dark
and light colored soils. Many of the prairies that are










dry during a considerable part of the year have light
sandy soils, the organic matter having been oxidized.
Those prairies that are partly flooded retain proportion-
ately more of the organic matter which gives the soil a
dark color. Several of the larger prairies or savannas of
the State are described in the Third Annual Report of the
Florida Geological Survey, pp. 43-76, 1910.

ALLUVIAL LANDS.

Many of the streams and rivers of Florida have flat
bottomed valleys densely wooded with hardwood trees.
Within these valleys the streams are often confined to no
definite channel. During the summer, owing to the heavy
rains, together with the impeded flow through the trees,
the valleys are as a rule flooded. In many of these, the
stream could be confined to a central channel and by clear-
ing out the dense growth of trees a considerable part of
the valley made available for agricultural purposes. How-
ever, the expense of clearing land of this kind is con-
siderable, and notwithstanding its fertility, very little of
it as yet has been reclaimed, and only a very small
amount of the alluvial lands are now being used for
agriculture.
The alluvial valley of the Apalachicola River has a
width of from one to two miles. It has a rich sandy soil,
but is flooded at high stages of the river and has been
but little used. The native vegetation is a dense growth
of hardwood timber. The Apalachicola, unlike the other
rivers of Florida, receives its headwaters from the Apa-
lachian Mountains, and is less affected by the rainy season
of Florida than by the melting of the snows of the moun-
tains.
Those streams which flow through limestone country
carry little or no sediments in suspension. Their channel
is cut chiefly by solution. Such streams have sandy banks
and little or no alluvial lands.










SWAMP LANDS.

The term swamp is applied to overflowed land support-
ing a growth of trees. The swamps of Florida were
described and classified in the Third Annual Report of
the Florida Geological Survey, 1910. It is probable that
the total swamp area of the State aggregates not less
than 3000 square miles, much of which is capable of being
drained and utilized.

MARSH AND MUCK LANDS.

When land is overflowed during all or nearly all of the
year, the growth of vegetation falls beneath the water,
is protected from decay and accumulates to form muck.
When drained the muck lands make fertile soils. The
muck lands may or may not support a timber growth.
The term marsh is applied to overflowed lands devoid
of timber but supporting a heavy growth of coarse grass.
Marshes may be of salt or fresh water. The salt or-marine
marshes are found bordering the coast and have been
built up by the tide. They consist largely of silt, mud
and clay with an admixture of organic matter. The
marine marshes being within range of the tides can be
reclaimed only by diking, although if reclaimed they
would undoubtedly prove very fertile. The fresh water
marshes afford conditions favorable to the accumulation
of vegetable matter and are frequently underlaid by de-
posits of muck. The muck lands of Florida are extensive,
aggregating probably not less than 5000 square miles.
The largest single muck area is the Everglades of southern
Florida now being drained by the State. Many smaller
muck areas occur widely scattered throughout the State.

PHYSIOGRAPHIC DIVISIONS OF THE STATE.

The State as a whole may be divided into more or less










well marked natural divisions in which particular types
of soil predominate. In the following pages the more
conspicuous of these are briefly described, approximately
in the order of their location in passing across the State
from east to west and from north to south. It is some-
times assumed by those who are imperfectly acquainted
with Florida that the State presents great uniformity
and is lacking in diversity. On the contrary from an
agricultural standpoint the State is highly diversified, as
will be evident from the description of the natural divi-
sions which follows. The divisions here described were
largely suggested and outlined by R. M. Harper in the
Sixth Annual Report of the Florida Geological Survey,
1914.
The West Florida Pinelands embrace a large area of
country extending from the west line of the State east to
somewhat beyond the Apalachicola River, including parts
of Escambia, Santa Rosa, Okaloosa, Walton, Washing-
ton, Calhoun and Gadsden counties. As is invariably true
of large areas a considerable diversity of soil conditions
occurs. The prevailing type of country is non-calcareous
rolling well-drained pinelands. The rivers have developed
alluvial valleys. A limited amount of flatwoods are in-
cluded, found for the most part bordering the river val-
leys. Several large rivers cut across this area and flow
into the Gulf. The largest of these are the Apalachicola,
the Choctawhatchee, and the Escambia. In passing in-
land from the coast the elevation rises to from 250 to 300
feet above sea level, the highest elevation in the State
being found within this area in Gadsden County.

WEST FLORIDA COASTAL BELT.

The West Florida Pinelands are separated from the
Gulf by a narrow belt of country designated as the West
Florida Coastal Belt. This belt which is only a few
miles wide extends from the Ocklocknee River on the










east to and beyond the west line of the State and includes
the islands which border the coast, and a narrow strip
of the mainland. The dunes, most of which are now
quiescent, which border the mainland are within this
belt. The soils are variable, aside from the sandy soil of
the quiescent dunes, more or less muck and alluvial ma-
terial has accumulated in the bays and ponds back of the
line of dunes. The prevailing timber growth on the quies-
cent dunes is the spruce pine. Back of the dunes the
prevailing timber is the long leaf pine.

EUCREEt VALLEY HAMMOCK LAND.

The Eucree Valley and Holmes Valley Hammock lands
are small areas lying along the Choctawhatchee River
valley and included within the large area designated as
the West Florida Pinelands. The two areas are notable
as being characteristic examples of the influence of topog-
raphy on the development of soils. Each of these so-
called valleys represents in reality the transition ground
between the Choctawhatchee River Valley and the up-
lands .of the interior of the county. Euchee Valley lies
on the west side of the Choctawhatchee River and chiefly
on the north side of Goose Creek and the west side of
Sandy Creek, and consists of a succession of small hills
giving a decidedly rolling topography. The red clay sub-
soil on the slopes lies near the surface. The forest growth
is chiefly hardwood and short leaf pine hammock.

HOLMES VALLEY HAMMOCK LAND.

Holmes Valley, which lies east of the Choctawhatchee
River and bordering its tributary, Holr:es Creek, repre-
sents the transition ground in passing from the river
valley to the uplands of the interior. The area is from
one to three miles wide and extends in a north-east to
south-west direction a distance of 15 to 18 miles. The land










is rolling or hilly. The drainage is by small streams that
cut across the area and flow into Holmes Creek. The
native growth is short leaf pine and hardwood trees.
The suggestion has been made that Holmes Valley repre-
sents an old lake bottom, this idea being advanced to
account for the persistent fertility of the valley as well
as for the type of soil and hammock growth. The origin
of the so-called valley is, however, very evident. As this
area lies on the border line between the valley and the
uplands, the top covering of loose sandy soil is gradually
removed about as rapidly as formed. Under these condi-
tions the soil is rapidly renewed by the addition of newly
disintegrated material from beneath, thus keeping up the
fertility of the land. Under cultivation the surface wash
has in some instances become so rapid as to be detrimental
to the soils. In most instances excessive surface wash can
be prevented by proper terracing. The hammock growth
which is native to this type of soil is due to the soil and
drainage conditions.

WEST FLORIDA LIMESTONE BELT.

The limestone belt of west Florida includes the north-
ern part of Walton and Washington counties and nearly
all of Holmes and Jackson counties. Limestone is exten-
sively exposed at the surface along the Chipola River in
Jackson County, and is occasionally exposed in the
northern parts of Washington and Walton counties.
Where not actually exposed it lies at no great depth.
The near approach to the surface of the underlying lime-
stone is in fact the chief distinguishing characteristic
between this area and the West Florida Pineland area
lying to the south and west. Near the Chipola River
and elsewhere where the slope is considerable and the
drainage good, red soils predominate together with hard-
wood and short leaf hammock growth. Long leaf pine is
found on the more level lands.











SAPALACHICOLA FLATWOODS.

The Apalachicola Flatwoods as here defined include
the southern part of Calhoun and Liberty counties,
nearly all of Franklin County, and the southwestern
part of Wakulla County. The land is level and shallow
ponds and bays are numerous. The Dead Lakes of Cal-
houn County are within this area. Long leaf pine is
the prevailing timber growth. The soils are for the most
part sandy or sandy loams, and are often dark colored
owing to the presence of organic matter. Muck deposits
are found in many of the ponds. Where the saw pal-
metto abounds a sub-stratum of hardpan is to be ex-
pected, but in the open flatwoods, large areas of which
are found on either side of the Apalachicola River, hard
pan is usually if not always absent.

MIDDLE FLORIDA HAMMOCK BELT.

The Middle Florida Hammock Belt extends witn some
interruptions through Leon, Jefferson, Madison, Suwan-
nee, Columbia, Alachua and Marion counties. Local
areas also occur in Holmes and Jackson counties and
are included in the west Florida limestone region al-
ready described. The drainage in the Middle Florida
Hammock Belt is affected by the underlying limestone.
The surface is rolling or somewhat hilly, and occasional
flat bottomed lakes are found which occupy solution
basins. The soils on the slopes are prevailingly red with
a red clay sub-soil. Surface streams are present, although
most of these terminate either in lakes or in sink holes
through which they gain entrance to the underlying lime-
stones, forming the disappearing streams characteristic
of this type of country. This belt occupies the border land
between the limestone and the non-limestone country. A
second well-marked belt of this type of country extends
north and south through Citrus, Hernando and Pasco
counties.
4-Class. Soil.











MIDDLE FLORIDA FLATWOODS.

The Middle Florida Flatwoods is a relatively narrow
belt of country which roughly parallels the Gulf and lies
inland from 15 to 25 miles from the coast. This belt
extends through and includes a part of Jefferson, Taylor,
Lafayette and Levy counties. The prevailing timber
growth is the long leaf pine interspersed with occasional
bays which support a dense swamp growth.

THE GULF HAMMOCK BELT.

The Gulf Hammock Belt is a strip of country which
borders the Gulf coast from near St. Marks to Tarpon
Springs. It is a limestone area and is in fact co-exten-
sive with that part of the Gulf coast in which the lime-
stone formations reach to tide-water. The underground
water level in this section is near the surface and
numerous large clear water springs emerge from the lime-
stone and flow to the ocean. This coastal strip contains
numerous large calcareous hammocks from which is
derived the name of Gulf Hammock Belt. This area ex-
tends through and includes parts of Wakulla, Jefferson,
Taylor, Lafayette, Levy, Citrus, Hernando, and Pasco
counties. A belt of similar country is found extending
north and south through Sumter County.

EROSION VALLEY OF THE SUWANNEE RIVER.

On either side of the Suwannee River in Florida is
found a level belt of well-drained land which is here desig-
nated as the erosion valley of the Suwannee River. On
the Seaboard Air Line Railway this type of country is
entered abruptly one or two miles east of Madison in
Madison County, while on the east side of the river this
type of country extends to the vicinity of Live Oak. Occa-
sional sink holes are seen which reach through to an un-











derlying limestone. The soils are sandy loams overlying
the limestone. Along the Withlacoochee River, a tribu-
tary of the Suwannee, this type of country extends to the
Georgia line, although on the Suwannee proper it ter-
minates somewhat above Suwannee Springs. Approach-
ing the Gulf the banks of the river become low and flooded
some miles below Old Town.

THE HARD ROCK PHOSPHATE BELT.

The Hard Rock Phosphate Belt is a characteristic type
of country paralleling the Gulf and lying inland 25 to 30
miles from the coast. On the Gulf side it borders the
Middle Florida Flatwoods. or where that belt is absent
the Gulf Hammock Belt. This belt extends in well-
marked development through Suwannee, Southern Colum-
bia, western Alachua, western Marion. Sumter, Citrus
and into Pasco counties. It is found also west of Ihe
Suwannee River passing through Lafayette, Taylor and
Jefferson counties, although in less well-deAined and
characteristic form. This belt is of great commercial
importance since it includes the hard rock phosphate
deposits. Few lakes or streams are found in the hard
rock phosphate belt, as the rainfall enters through the
loose surface material and passes directly into the under-
lying limestone. The underground water level lies as a
rule at a greater depth beneath the surface than in the
Gulf Hammock country. Numerous sinks form giving
evidence of the continued active erosion by underground
solution. The surface contour is rolling, there being no
regularity of hills or valleys. Well-drained sandy soils
predominate in this area.

THE LAKE REGION.

The Lake Region includes a large area extending north
and south through Clay, Putnam, eastern Marion, Lake,










Orange, and Polk counties and reaching into DeSoto
County. Lakes, as implied by the name, are extremely
numerous in this section of country. Surface streams
are few as a greater part of the rainfall passes into the
soils. The prevailing timber growth is the long leaf
pine with as a rule very little undergrowth. The soils
include chiefly light sandy loams overlying red sandy
clays. Peat and muck deposits are very abundant in the
Lake Region.

EAST FLORIDA PINELANDS.

The East Florida Pinelands include a large area lying
in the northeastern part of the State, including a part or
all of the following counties: Columbia, Baker, Bradford,
Nassau, Duval, Clay, Putnam, St. Johns, Flagler, Volusia,
Brevard, Okeechobee, St. Lucie, Broward, Osceola, and
Palm Beach counties. This area thus lies north and east
of the Lake Region previously described. While the area
presents much diversity the prevailing type of country is
non-calcareous pinelands. The type of open flatwoods is
more extensively developed within this area than else-
where within the State. Palmetto flatwoods also are not
lacking. The rise in elevation in passing inland from the
coast is quite sufficient for good drainage, but the area
is geologically recent and surface drainage has not fully
developed, the stream channels being for the most part
imperfectly developed. The prevailing timber growth is
the long leaf pine. Some large muck land areas are
found within this area particularly around the head wa-
ters of the St. Johns River.

THE ATLANTIC COAST HAMMOCK BIELT.

The Atlantic Coast Hammock Belt ic. a narrow strip
of hammock land which extends with some interruptions
along the Atlantic coast from St. Augustine to or be-
yond Rockledge, a distance of about 150 miles. This










hammock rests upon and is developed from the coquina
shell rock. The belt includes Turnbull and other well-
known hammocks along the east coast. The prevailing
vegetation is a dense growth of cabbage palmetto and
various hardwood trees.

ATLANTIC COAST DUNES.

A line of sand dunes extends with some interruptions
from Fernandina at the northern line of the State south
to New River in Dade County. The dunes are for the
most part quiescent and support a growth of spruce pine.
They lie back of the calcareous hammock belt being in-
land from one to two miles from the present coast. It
is probable that the sand dunes are contemporaneous
with the coquina rock. This part of the east coast for-
merly stood at a lower level and the sand dunes when
formed were directly on the coast. The coquina rock
accumulated in the shallow waters bordering the coast.

SOUTH FLORIDA PINELANDS.

The South Florida Pinelands cover a large part of
southern Florida. The prevailing timber growth is the
long leaf pine, which, however, gives place in the south-
ern part of this area to the Cuban pine. This large area
presents considerable diversity. The prevailing soils are
sandy loams frequently underlaid by clayey limestone
or shell marls. The Caloosahatchee River, which crosses
this area from Lake Okeechobee to the Gulf, is bordered
by calcareous hammock lands. Extensive areas of ham-
mock and muck lands are found along the Manatee River.

SOUTHERN GULF COAST DUNES.

An irregular and more or less interrupted line of dunes
occurs along the southern Gulf coast. Some of the best











developed of these dunes are seen on the islands near
Caxambas: Pass in the southern part of Lee County. Low
quiescent dunes are seen along the coast line of Manatee
County south of. Sarasota. These sand dunes like those
of the east coast are quiescent and support a growth of
spruce pine and various shrubs.

THE EVERGLADES MUCK LANDS.

The Everglades of Southern Florida include an area
of. about 4,000 square miles, lying south and east of Lake
Okeechobee. Over this area muck deposits of consider-
able, although varying, depths rests upon a limestone
foundation.

THE MIAMI IAlMESTONE BELT.

The Miami Limestone Belt extends north and south
through Dade County lying between the east border of
the Everglades and the Atlantic coast. The underlying
formation is an ooliltic limestone which is exposed at the
surface or covered by a shallow coaling of sandy or muck
soil. The prevailing type of vegetation is the Cuban
pine with a dense undergrowth of saw palmetto.

DADE COUNTY PRAIRIE BELT.

The Dade County Prairie Belt is a strip of prairie land
bordering the coast and extending south-westward from
Cocoanut Grove. The land lies close to sea level and is
more or less inundated by salt water during storms and
supports a sparce growth of mangrove bushes.

MANGROVE SWAMPS.

Mangrove swamps form a characteristic feature of the
southern Florida coast. The largest of the mangrove










swamps are those which lie along the Gulf coast extend-
ing from Whitewater Bay back of Cape Sable to Cape
Romano, including the Ten Thousand Islands. The man-
grove trees of the Shark River Archipelago and the
southern portion of the Ten Thousand Islands, as re-
ported by Sanford in the Second Annual Report of the
State Geological Survey, reach the unusual size of 60 or
more feet in height, and 2 or more feet in diameter at the
butt. Elsewhere the trees are as a rule of smaller size,
being usually under 20 feet in height. Mangrove swamps
are found more or less well developed from somewhat
north of Miami on the Atlantic coast to Marco on the
Gulf coast.

THE FLORIDA KEYS.

The Florida Keys include a line of islands extending
from Soldiers Key opposite Miami to Key West. The
keys may be divided into two groups. The first of these,
extending from Soldiers Key to and including Knights
Key, has a coral limestone foundation and supports a
dense growth of hardwood and palm trees. Beyond
Knights Key the islands are more irregular in shape ani
rest upon a sub-structure of oolitic limestone. The Cuban
pine is a conspicuous feature of the vegetation of this
lower group of keys.




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