60 
FLORIDA state; geological survey. 
In subsequent publications by the same author this rock was called 
the “Nummulitic” limestone, but, in 1892, Dali 1 proposed the name 
Ocala limestone. 
Stratigraphic Position:—The Ocala limestone lies stratigraphically 
between the “Peninsular” and the beds here designated Apalachicola 
group. Lithologically, it bears a strong resemblance to the underly¬ 
ing “Peninsular” limestone, with which it also has a close faunal re¬ 
lation. These facts have led to the conclusion that the two formations 
are conformable, and it has also been suspected that the Ocala lime¬ 
stone represented a local phase of the “Peninsular.” While the two 
formations are probably conformable, the extensive distribution of the 
nummulites of the Ocala limestone shows that it represents a wide¬ 
spread change in conditions and is not to be classed as a mere local 
phase of the underlying beds. 
The Ocala limestone, as already noted by Johnson, 2 is sometimes 
wanting, so that the overlying formations rest directly upon the 
“Peninsular.” This relation was noted at several localities which 
will be mentioned in discussing the younger formations. At.present it 
is sufficient to note its absence and to suggest that since the Ocala 
limestone does not appear to be a local phase of the “Peninsular,” 
there is probably a stratigraphic break between the rocks belonging 
to the Vicksburg and Apalachicola groups in the central part of the 
peninsula. 
Lithologic Character: — The Ocala limestone consists of a soft, 
porous, light-gray to white limestone which bears a strong lithologic 
resemblance to the underlying “Peninsular” limestone, but is dis¬ 
tinguished from it by the included fossils. When slightly weathered, 
the rock becomes light yellow, and owing to its granular appearance 
is often regarded as sandstone. The removal of the calcareous ma¬ 
terial by the leaching action of underground water leaves a pale yellow, 
more or less incoherent sand, containing a small percentage of calcium 
carbonate. When fresh, the Ocala limestone is so soft that it is easily 
broken, but exposed surfaces often become hardened by the deposition 
of calcium carbonate from the waters which emerge along the outcrop. 
For this reason the rock frequently appears to be hard and firm. Its 
porosity and ready solubility permit the formation of numerous under¬ 
ground channels which are sometimes seen at the outcrop and are 
inferred from the presence of numerous sink-holes. The rock con¬ 
tains an abundance of organic remains which are commonly preserved 
as casts. Nodules and large masses of chert are also common and in 
some localities a large part of the rock has been silicified. 
1 Dali, Wm. H. Neocene of North America, U. S. Geol. Surv., Bull. 84, 1892, 
pp. 103-104. 
2 Johnson, Lawrence C. Op. cit. 
