IIO FLORIDA GEOLOGICAL SURVEY-NINTH ANNUAL REPORT. 
assumed to be probably of Pliocene age. In view of the lack of 
definite information as to these superficial deposits, it is difficult to 
assert that they may not be. a part of a Pliocene formation. How¬ 
ever, such an assumption seems unwarranted, inasmuch as there is 
no clear evidence to show that they are not a part of the Alum Bluff 
formation which is known to extend over this area. 
PLEISTOCENE. 
The fossil remains of the land animals of the Pleistocene period 
have been found at several localities within this area. From 
Wakulla Springs has been taken numerous proboscidian bones. A 
number of bones of the mastodon or the elephant' taken from this 
spring many years ago are. said to have been lost by shipwreck while 
being transported to Washington. No fossiliferous marine Pleis¬ 
tocene beds have been detected, although such may be expected near 
the coast, especially in the southwestern part of this area, where the 
dip carries the older formations below the surface. 
The harbors of the Gulf Coast of Florida represent with little 
doubt flooded stream valleys* and indicate a slight submergence 
from a higher elevation which occurred probably during the Pleis¬ 
tocene period. The Wakulla River was probably at one time a 
tributary to the St. Marks River, although at the present time the 
two streams unite, at tide water. The Sopchoppy River was like¬ 
wise probably formerly a tributary to the Ocklocknee River, 
although at present it flows into Ocklocknee Bay, which is the 
flooded mouth of the Ocklocknee River. 
*The Geological History of Harbors. By N. S. Shaler, U. S. Geol. Survey, 
13th Ann. Rpt, pt. 2, 1893. 
i 
