90 
FLORIDA STATE-GEOLOGICAL SURVEY. 
of the pit, the clay becomes gray and is interbedded with thin nodular 
layers of limestone. 
A light green siliceous clay similar to that described above was 
seen on the west side of Old Tampa Bay, near Safety Harbor (Espir- 
itu Santo Springs). Here the section shows four to six feet of white 
Pleistocene sand resting unconformably upon six feet of greenish 
clay. On the beach, near this exposure are several large chert bould¬ 
ers which were probably derived from beds beneath the clay. About 
one mile'north of the postoffice the following section was observed: 
White Pleistocene sand ... 2-4 feet. 
Dark brown sand, partially indurated...... 1-6 feet. 
fjght greenish clay, thinly laminated.... 5 feet 
On the Gulf coast, near Clearwater^ are numerous exposures of 
cherty limestone which are probably to be correlated with the rocks 
at Tampa, but in the absence of paleontologic evidence, this correlation 
must be regarded as merely tentative. A generalized section at this 
locality was obtained from well records and observations along the 
beach. 
1. White Pleistocene sand . 12 feet. 
2. Light colored clay . 14 feet. 
3. Light colored limestone with chert concretions. 1 ft. to 6 in. 
4. Bluish laminated marly clay with chert concretions... 2-4 feet. 
5. Light gray limestone with chert concretions. 2-3 feet- 
A generalized section near Laporitieres Spring is given by Dali i 1 
Humus, yellow sand, etc. ... 6 to 36 inches. 
Tampa limestone . 10 to 15 feet. 
Orthaulax bed . 7 in, to 10 ft. 
The limestone of the Tampa formation is exposed near the pump¬ 
ing station, where it has been quarried to a depth of over fifteen feet, 
and other exposures occur at intervals along the Hillsboro River for 
a distance of over fifteen miles inland. Probably the best exposures 
are in the excavations near the Sulphur Spring, northeast of Tampa, 
and at the rapids about a mile above the spring. The same limestone 
was observed resting on the “silex bed” at the railroad crossing over 
Six-Mile Creek. Here the limestone is immediately overlain by fos- 
siliferous Pleistocene shell marl which grades upward into coarse 
white sand. 
Section one-eighth mile below railroad bridge—Orient {Tampa). 
4. Soft white marl . 6 feet. 
3. Light gray to buff fine grained quartz sand. 3 feet. 
2. Gray shell marl Pleistocene . 1-2 feet. 
1. White soft limestone with some gastropods and other fossils. 5 feet. 
1 Dall, Wm. H., Neocene of North America, U. S. Geol. Survey, Bull. 84, 
1892, p. 108. 
