206 FLORIDA GEOLOGICAL SURVEY— 15 TH ANNUAL REPORT 
SARASOTA COUNTY 
Sarasota County is situated in southwest Florida and borders on the 
Gulf coast just above Charlotte Harbor. Its surface materials are chief¬ 
ly sands and marls. No important clay deposits are known within rea¬ 
sonable distance from transportation. 
SEMINOLE COUNTY 
Seminole County is located in the east-central part of the peninsula 
in the upper St. Johns Valley. Sandy surface clays containing a coarse 
quartz sand and very desirable for sand-clay roads are widely distributed 
over the county. No clays suitable for manufacturing products are 
known. 
SUMTER COUNTY 
Sumter County is located in the west-central part of the peninsula 
and is bordered on the west by the Withlacoochee River. The Ocala, 
Tampa and Alum Bluff formations comprise the greater part of the 
surface materials. These consist chiefly of sands and sandy clays. 
Residual clays from the Ocala limestone occur locally in the north¬ 
ern part of the county. Few of these, however, may be used for manu¬ 
factured products. 
A few somewhat sandy clays of limited extent occur in the eastern 
part of the county. One of these is found at the Atlantic Coast Line 
station at Webster. It probably underlies a considerable area and is 
more than four feet in thickness. The overburden is about three feet 
of sand and soil. Only a soft, porous building brick of very inferior 
quality can be made from this clay. It has the following physical prop¬ 
erties : 
Physical Properties of the Webster Clay (Lab. No. 0-75). 
Plasticity, judged by feel. Good. 
Water of plasticity. 25.90% 
Pore water . 1.55% 
Shrinkage water . 24.35% 
Linear air shrinkage. 10.8 % 
Volume air shrinkage. 29.6 % 
Modulus of rupture, average. 328.5 pounds per square inch. 
Slaking test .... 5 minutes. 
