THE SOILS OF FLORIDA. 19 
to the uplift that occurred during or at the close of Pleistocene time. 
It is probable that the coquina rock was formed near the close of 
this period of uplift as it is now found only a few feet above sea 
level. 
UNCLASSIFIED GRITS, SANDS, AND SANDY CLAYS. 
In addition to the formations described there is found in Florida 
an extensive deposit of sand, gravel and lenses of clay. This material 
forms the surface covering over a large extent of northern and cen¬ 
tral Florida as well as parts of the adjoining States. It is found 
entirely across the State from the Alabama line on the west to the 
Atlantic coast, and is found over the central part of the peninsular 
section as far south as DeSoto County. The classification of this 
superficial material has given rise to much difficulty owing chiefly 
to the fact that in Florida it is practically non-fossiliferous although 
a few plant remains have been found. It has been regarded in recent 
years by most writers as Pliocene in age, although as a matter of 
fact there is no satisfactory evidence that it may not be early Pleis¬ 
tocene. Moreover, it is quite possible that more than one formation 
or parts of formations are included under this head, the absence of 
fossils making it difficult to discriminate formation lines. 
In the literature, this material will be found referred to most 
frequently as the Lafayette formation. The Lafayette formation 
was named by Dr. E. W. Hilgard, the type locality being at Oxford, 
in Lafayette County, Mississippi, where the formation is well ex¬ 
posed. This locality has recently been re-examined by Berry who, 
upon the evidence of the fossil plants finds the deposits to be of 
Eocene age.* From this evidence it would appear that the Florida 
material can not be correlated with the Lafayette as defined from 
the type locality, since in Florida the material everywhere rests 
upon deposits later than Eocene. 
In his presidential address before the section of Geology of the 
American Association for the Advancement of Science in 1906, Pro¬ 
fessor E. A. Smith discussed the geology of the Gulf Coast. In regard 
to Florida, referring particularly to the western extension of the 
State from the Apalachicola Biver to the Alabama line, Smith at 
that time regarded the upper part of these deposits, the red sands 
and loams, as Lafayette, and the more or less stratified clays, sandy 
clays, and sands beneath, as representing the Grand Gulf formation. 
The Grand Gulf formation was also established by Hilgard, the type 
locality being Grand Gulf, Mississippi. 
^Journal of Geology, Vol. XIX, pp. 249-256, 1911. 
