112 
FLORIDA GEOLOGICAL SURVEY—14TH ANNUAL REPORT 
cast boundary of the county, the Alum Bluff and Choctawhatchee forma¬ 
tions are at the surface. Localities where these formations may be seen 
are as follows: Chattahoochee formation at Rock Bluff, in the north¬ 
western part of the county, and on various streams in this part of the 
county; Alum Bluff formation at Alum Bluff on the Apalachicola River, 
and at numerous localities on the Ocklocknee River through the county; 
the Choctawhatchee formation may be seen at Alum Bluff on the 
Apalachicola River, and at Jackson Bluff on the Ocklocknee River, and 
also at many localities on small streams in the central part of the county. 
The dip of the formations in this county is in general southward. In 
the northwestern part of the county the direction of maximum dip may 
be somewhat east of south, while in the southeastern part of the county 
the maximum dip is probably west of south. 
MADISON COUNTY 
Madison County borders the Georgia state line and lies west of the 
Withlacoochee and Suwannee Rivers. In the southern part of this 
county the Chattahoochee limestone is at or near the surface. In the 
northern part of the county this formation, for the most part, is con¬ 
cealed by the Alum Bluff formation, but is occasionally exposed in sinks, 
stream valleys and lake basins throughout the county. The surface ma¬ 
terials include red, sandy clays and sands of undetermined age. The 
Ocala limestone possibly comes to the surface on the Suwannee River in 
the southeastern part of the county. No record of deep wells has been 
obtained in this county. 
MANATEE COUNTY 
In Manatee County the Alum Bluff formation (Miocene) lies either 
at the surface or at no great depth below the surface. In the northwest¬ 
ern part of the county this formation may be seen exposed in the banks 
of the Manatee River. In the interior of the county it is covered by later 
deposits, probably, chiefly by Pliocene deposits which are equivalent in 
age to the Bone Valley formation. Thin Pleistocene shell marls are 
found at some localities near the Gulf coast and may be seen in pits 
opened up for road material at Bradentown. The Tampa formation 
(Oligocene) and the Ocala formation (Eocene) probably are present, 
underlying the surface formations. No wells of great depth have been 
