PRELIMINARY REPORT ON PEAT. 
227 
The soil is nearly everywhere sand, where it is not covered by 
still more recent deposits, such as peat. Clay seems to be absent, 
and the limestone is often close to the surface, or barely exposed, 
as in the Gulf hammock region. Long-leaf pine is the prevailing 
tree as far south as Brevard and DeSoto Counties, and south 
of that it is replaced by a related species (Pinus Caribaea) * Saw- 
palmetto is the prevailing undergrowth nearly everywhere. The 
whole region is dotted with prairies of all sizes, from a few acres to 
several thousand square miles (if the Everglades be regarded as 
a prairie) in extent. 
This region has been too little explored scientifically to warrant 
any definite statement about the quantity of peat it may contain, but 
there are certainly many shallow deposits in and around some of 
the prairies, lakes and estuaries. The northern part of the Ever¬ 
glades, which is the most extensive (through not the deepest) de¬ 
posit of peat in Florida, if not the largest in the United States, 
may be regarded as belonging to this region. Descriptions of this 
and a few other interesting South Florida peat localities will be 
found in the following pages, and analyses under localities n, 2i, 
28 and 80. 
MIAMI LIMESTONE REGION. 
(PLATES 2.2, l8, FIGS. 27, 28) 
From the vicinity of Fort Lauderdale there extends southwest- 
ward a belt of honeycombed limestone rockf of Pleistocene age, 
with a maximum elevation of about 20 feet above sea-level, form¬ 
ing a part of the rim of the Everglades. North of the latitude 
of Cocoanut Grove this rock is covered with sand, at first only a few 
inches deep, or merely filling the holes in the rock, but becoming 
deeper northward. Southward of the point named, the rock is al¬ 
most bare of anything but vegetation and a small quantity of humus, 
except in the vicinity of Homestead, where there are small areas in 
which the interstices of the rock are filled with a sort of reddish clay, 
*For notes on the distribution of this tree in Florida see Tenth Census U. S., 
vol. 6, p. 207, and agricultural map facing p. 187. (It is there called “pitch pine”). 
fSeveral botanical writers in recent years have called this “coral rock,* 
or “coralline limestone,” its honeycombed appearance probably leading them to 
imagine that it was an ancient coral reef like the upper Keys (which will be 
described farther on) ; but geologists have known for years that it is nothing of 
the kind. It does contain a few corals among its fossils, like many other lime¬ 
stones, but these corals form only a minute fraction of the whole mass, and 
they are not reef-building species, anyway. All this was brought out pretty 
clearly by Mr. Sanford in the second annual report of this Survey. 
