AGE OF THE UNDERLYING ROCKS OF FLORIDA 
IOI 
well on Key Vaca in southernmost Florida the Ocala is replaced by 
a foramini feral fauna very much like that of the West Indian re¬ 
gion at that time. 
In the region northward from Tiger Bay the Ocala is present 
except about Apopka, where it was either eroded or not deposited, 
due to that area being at that time a land mass. If the Apopka 
region was an island during the deposition of the Ocala there 
should be evidence of this fact in the character of the Ocala as it 
approaches. From the fact that there is no evidence of the Lep- 
idocyclina of Ocala age at Eustis, but as Nummulites of the lower 
bed do occur and as both are absent so far as seen at Apopka tends 
more to the idea that both have been eroded at Apopka than not 
deposited at all there. 
Perhaps the most striking thing in connection with the Ocala 
is the finding that it is apparently only about 40 feet thick and that 
this thickness is very uniform. Various estimates in the literature 
give its probable thickness from two or three hundred to over a 
thousand feet. Some of the higher of these estimates were based 
on certain of the wells here considered. This thickness has undoubt¬ 
edly come from the finding of the Ocala species through long series 
of well samples but represent simply specimens that have fallen 
from above. The limiting bed of thick Nummulites that lies de¬ 
veloped just below the Ocala at Anthony and other places makes 
certain this greatly reduced thickness over previous estimates. 
This erosion more probably took place when the area here and 
westward was above the water during a period probably late Olig- 
ocene and formed the area named by Vaughan ( 1 . c. p. 182) “Or¬ 
ange Island.” this area may have been an island in the Ocala sea. 
The section between Apopka and Anthony passing through Eustis 
shows that there is apparently a slight syncline in the Lower Creta¬ 
ceous in this place. This may tend to show that the Lower Creta¬ 
ceous is not a simple great low anticline but that there may be 
numerous secondary minor flexures. This would indicate that there 
was at least some slight folding before the deposition of the Ocala. 
Also the known vertical distance between the Ocala and the under¬ 
lying Lower Cretaceous ranges from around 60 feet at Anthony to 
250 feet or more in some of the other wells. All these indications 
point toward an unequal level of the upper Orbitolina bed at the 
