PRELIMINARY REPORT ON PEAT. 
217 
fronted at the outset with what appears to be a serious difficulty; 
namely such prominent features a's lakes, hammocks,* flat woods, 
prairies, lime-sinks, scrub, etc., are widely scattered over the state, 
in what might seem at first to be inextricable confusion. But by 
careful study it is possible to locate a well-defined lake region, a 
lime-sink region, two or three hammock regions, several flatwoods 
regions, etc. 
Before defining these regions it will be well to explain in a few 
words the geological structure of Florida. The entire State is un¬ 
derlaid by limestone, of various ages from Vicksburg to Recent, 
and that is covered in most places by several feet of clay (mostly 
Pliocene ) or sand (mostly Pleistocene) or both. The character of 
the country at any particular place is determined principally by the 
amount of clay or sand on top of the limestone, the elevation above 
sea-level, the time elapsed since it last emerged from beneath the sea, 
and the average dcoth of the ground-water below the surface. 
(These characters in turn are all more or less dependent on each 
other, in various intricate ways). 
The map accompanying this report (plate 16) divides the State 
iifio about twenty geographical divisions of varying rank, some of 
them more distinct than others. Some which are very small, or 
imperfectly understood, or which contain little or no peat, are 
shown merely for the sake of completeness, and for suggestions to 
future explorers, and will not be described in the text. 
It is scarcely necessary to remark that this map is only a pre¬ 
liminary one, and future investigations may change it consider¬ 
ably. For some of the boundaries are rather vague at the best, 
and even where they are very distinct their location has been 
verified only at a comparatively few points (such as where they are 
crossed by railroads), and guessed at the rest of the way. More¬ 
over, there will always be differences of opinion as to how far the 
process of subdivision should be carried, as is the case in nearly all 
classifications of things. 
*Many residents of other states who have written about. Florida have at¬ 
tempted to define “hammock” (a term which is used in Florida more than in 
all the rest of the world), but most of them have missed the mark by trying- to 
correlate it with soil. A hammock is nothing more nor less than a certain type 
of vegetation : namely, a comparatively dense growth of tr^e other than pines, 
in comparatively dry soil (or at least not wet enough to be called a swamp), 
in a region where open pine forests predominate. The ground in such places is 
always covered with more or less humus derived from the trees, but immediately 
under the humus the soil may be either sand, clay, marl or limestone. An inter¬ 
mediate condition between hammock and swamp is often called low hammock. 
The desirability of hammock land for agricultural purposes is due primarily to 
its humus. 
