OCKLOCKNEE AND AUCILLA RIVERS. IO9 
sands, may also belong in whole or in part to the same formation. 
In Leon and Wakulla counties the deposits appear to be thin, 
.although there is little opportunity to measure the formation as a 
whole. The area in Leon and Wakulla counties known to be cov- 
>ered by this formation, as indicated on the map, is limited and is 
■confined to the. belt of country near the Ocklocknee River. The 
formation is not known to extend into Jefferson County. 
Inasmuch as the marine phase of this formation extends into 
the southwestern part of this area, it may be suggested that possibly 
the uppermost sands and clays of the northern part of the area rep¬ 
resent the shoreward margin of the same formation. This is, per¬ 
haps, a possibility, although in the absence of any definite proof it 
-seems unsafe to assume a complete. Miocene submergence of the 
whole area. 
TYPICAL EXPOSURES 
Perhaps the best single exposure of the Choctawhatchee forma¬ 
tion within this area is that seen at Jackson Bluff, where six or seven 
feet of shell marl represent the marine fossiliferous phase of the 
formation. This marl is also seen at a number of other places far¬ 
ther down stream, as well as in many of the small streams entering 
the Ocklocknee River. The presence of this marl has been noted 
on Duggar Creek in Section 9, T. 1 S., R. 2 W.; also near Hugh 
Black’s sawmill on Mill Creek.* The shell marl passes below the 
hed of the stream before reaching the Gulf Coast. 
PLIOCENE. 
No marine Pliocene deposits have been recognized within this 
area. On New River, however, in Franklin County, the writer 
found a limestone bed containing fossils which have been identified 
hy Dr. T. W. Vaughan as probably representing the Miocene or the 
Pliocene.f If the. Pliocene is present at this locality in Franklin 
County it is very probable that deposits of this period extend 
into the southwestern part of Wakulla county. The red sandy 
clays of Leon and Jefferson counties were, as already stated, for¬ 
merly placed in the Lafayette formation, and at that time were 
*Fla. Geol. Surv. Rept., Second Ann. Rept., p. 121, 1909. 
tPersonal letter of Dec. 16, 1915. 
