THE SOILS OF FLORIDA. 21 
One of the localities where this coarse material is found and where 
it has been extensively mined for road purposes is at Interlachen, in 
Putnam County. The section in the pit of the Interlachen Gravel 
Company is as follows: 
Coarse sand and gravel, light colored or ochre yellow. 3 ft. 
Sand and gravel iron stained red, and feebly cemented.... 5 ft. 
Light colored coarse sand and gravel.. 5 ft. 
Another locality from which similar coarse material is obtained 
for road purposes is found near Grandin and Florahome in the same 
county. The pebbles are frequently one inch or more in length. Equal¬ 
ly coarse pebbles are found along the line of the St. Andrews and At¬ 
lanta Railway a few miles south of Cottondale. It has been sug¬ 
gested that the coarse material in these deposits is found along the 
line of the principal rivers. It will be noted, however, that the three 
localities mentioned in Florida at which specially coarse material 
is found are all of them remote from any present river channel. 
The clay intermixed with the coarse sand is in a finely divided 
condition and is probably the chief cementing material, giving the 
sand feeble coherence sufficient to form vertical walls. In addition 
to the clay it is probable that silica acts to some extent as a cement 
particularly in the few localities in which the sand becomes firmly 
cemented forming a hard rock. Iron oxide and probably iron car 
bonate act also as cements. The clay in the sand is frequently in the 
form of a ball clay or plastic kaolin, the ball clays mined at Edgar 
and near Leesburg coming apparently from these deposits. The clay 
strata and clay lenses include greenish and variegated clays. 
Mica is intermixed with the sands and clays, and is removed 
from the ball clay in the process of mining. The mica is in the form 
of small flakes, a fraction of an inch in length. 
The materials of these deposits are somewhat indefinitely strati¬ 
fied and frequently cross-bedded. Aside from the cross-bedding, dis¬ 
tortion of the strata is frequently observed. This, however, is due 
in most if not in all cases to partial subsidence owing to solution in 
the limestones beneath, or to creep on the slopes. That the deposits 
were formed in shallow water and in the presence of conflicting 
currents is evident from the irregular stratification and the variable 
character of the material. 
The admixture of finely divided clay kaolinitic in nature, with 
the coarse sands which characterizes these deposits is difficult to 
account for except upon the hypothesis that when deposited the for¬ 
mation consisted of coarse quartz and feldspathic sands. The 
quartz being resistant has remained but little changed, forming the 
