5 2 FLORIDA GEOLOGICAL SURVEY TENTH ANNUAL REPORT. 
PLIOCENE. 
Marine Pliocene deposits have not been definitely determined, 
although limestone found on New River in Franklin county may be 
of this period. A small collection of fossils from this rock has been 
kindly identified for the Florida Geological Survey by Dr. T. W. 
Vaughan of the U. S. Geological Survey. The fauna from this de- 
posit, as reported by Dr. Vaughan, include the following: 
Pecten comparilis, Tuomey & Holmes; Range, Miocene. 
Pecten mortoni, Ravenel ; Range, Miocene-Pliocene. 
Pecten raveneli, Dali. ; Range, Miocene-Pliocene. 
Plecatula marginata, Say; Range, Miocene-Pliocene. 
Pecten sp. 
Ostrea sp. 
Bryozoa. 
Barnacles. 
Correlation : Miocene or Pliocene. 
The stratigraphic position of these limestones suggests that 
they are probably Miocene. 
PLEISTOCENE. 
No marine fossiliferous Pleistocene has been found in this area. 
The harbors of the westward extension of Florida are regarded as 
representing the flooded mouths of stream valleys. If this is true, 
the submergence which produced these harbors has possibly con- 
cealed the fossiliferous Pleistocene of this part of the coast. 
THE SURFACE MATERIALS. 
The surface materials in this area include, in places, a consid- 
erable thickness of light-colored incoherent sands. The maximum 
observed deposit of this sand is found in the Alum Bluff section, 
where it is 21 feet thick. The sand grains are, as a rule, small and 
well rounded. On the east side of the Apalachicola river a belt of 
this sand extends from near Rock Bluff to Bristol, a distance of 8 
or 10 miles. Both north and south of this belt there is much less 
sand at the surface. On the line of the Apalachicola railway this 
sand belt extends from about 1 mile north of Sedalia to near Hos- 
