PETROLEUM POSSIBILITIES OB FLORIDA 
65 
GEOLOGIC MAP 
The surface distribution of the formations is indicated on the accom¬ 
panying geologic map. On this map surficial materials are to a degree 
neglected and the deeper formations are -mapped over areas in which 
they, in some instances, only occasionally outcrop. Thus in the large 
area in central peninsular Florida mapped as Ocala, the outcrops of 
this formation are by no means continuous, this formation being very 
commonly mantled by remnants of the Alum Bluff formation, and in 
places by the reworked products of the Alum Bluff and other forma¬ 
tions which now constitute the Alachua formation. A detailed map on 
a larger scale would show within the area here assigned to the Ocala, 
isolated remnants of the Alum Bluff formation as well as of the Alachua 
formation. Likewise the considerable area, particularly in west Florida 
and on the Atlantic coast mapped as Pleistocene and Pliocene, includes, 
as indicated, more or less undifferentiated formations, some of which 
possibly will be found to be older than the Pleistocene or Pliocene. 
The mapping of the Choctawhatchee formation, upper Miocene, pre¬ 
sents difficulties owing to the fact that it is very thin and is frequently 
cut through by streams. To the east, the shell marl phase of this forma¬ 
tion seems definitely to end somewhat west of Tallahassee. Its exten¬ 
sion to the west is much less definitely known, although the westernmost 
fossiliferous locality seen at the surface is that at Red Bay, in Walton 
County. The mapping of the formation as extending farther to the 
west is therefore hypothetical. On the geologic map it is shown to ex¬ 
tend westward to the Alaqua Creek in central Walton County. This 
mapping of the westward extension of the formation is by Dr. C. Wythe 
Cooke. 
The mapping of the Upper Miocene, as extending to the gulf through 
Franklin County, is hypothetical except in so far as supported by a 
fossiliferous locality on New River which indicates either Miocene or 
Pliocene. (See page 103.) 
The Chattahoochee and Alum Bluff formations west of the Apalachi¬ 
cola River have been mapped by C. Wythe Cooke. These forma¬ 
tions east of this river are mapped as the surface formations in the 
northern part of Leon, Jefferson and Madison Counties. As a matter 
of fact, there is quite generally spread over this area a superficial de¬ 
posit of red sand and clay, the age and relationship of which is undeter- 
