228 FLORIDA GEOLOGICAL SURVEY-THIRD ANNUAL REPORT. 
which however has no connection with the Pliocene clay of north¬ 
ern Florida. The same rock extends out into the southern part of 
the Everglades to an undetermined distance. 
Strange to say, the Miami limestone, unlike nearly all other 
limestones, seems to have very little effect on vegetation. The 
drier parts of it are covered with forests of pine (Pinus Caribaea) 
with a dense undergrowth of saw-palmetto, essentially similar in 
aspect to the forests of the southern part of the South Florida 
flatwoods; and the parts subject to occasional inundation are tree¬ 
less, like the prairies in the region just named. The upland forest 
sometimes known as the Biscayne pineland, which has a maximum 
width of about ten miles, is dotted with hammocks varying in ex¬ 
tent from one to several hundred acres, in which the trees are nearly 
all of tropical species, but probably not necessarily lime-loving. 
The water-level in the Everglades fluctuates considerably with 
the seasons, so that there are large areas around the edges which 
are dry in spring and inundated in fall, like the ponds and shallow 
lakes of northern Florida.* In this part, however, there are 
many depressions which are permanently wet, and peat accumulates 
in these in the same way as in the deeper holes in the prairies of the 
Middle Florida hammock region. Some estuarine peat is also 
found along the Miami River and other streams. 
Analyses of peat from this region will be found under localities 
24 to 27. 
COAST PRAIRIE. 
Bordering the Biscayne pineland from Cocoanut Grove souch- 
westward, and extending all the way to the coast, which is no¬ 
where more than ten or twelve miles away, is a flat prairie so slightly 
elevated above the sea that it must be inundated by salt water in 
times of storms or exceptionally high tides. It is dotted with 
dumps of bushes and small trees like the southern part of the 
Everglades, and by some botanists it has been considered a part of 
the Everglades. There are various minor differences in vegetation 
between the coast prairie and the Everglades, however, (as might 
be expected from their different relations to salt water), and one 
very marked difference in aspect. Everywhere in the coast prairie 
except within a mile or two of the pine land there are millions of 
*For a popular account of some explorations at the south end of the 
Everglades in the dry season, with references to some earlier literature on the 
same region, see Florida Review (Jacksonville) 4:44-55. 147-157. July and 
August, 1910. 
