260 
FLORIDA STATE GEOLOGICAL SURVEY. 
Feet. 
Sand and clay . 1 - 20 
Sand and dark colored marl. 20- 40 
Marl and medium hard rock. 40-100 
Light colored hard rock.. 100-105 
Medium hard rock . 105-175 
Light colored hard rock . 175-190 
Shell-bearing medium hard rock . 190-215 
Soft shell-bearing rock..... 215-266^4 
TAMPA. 
The water supply for the city of Tampa is obtained from 
drilled wells, of which there are twenty-eight at present. The 
wells range in depth from about 200 to 325 feet. Wells at a 
greater depth, as a rule, reach salty water. The wells are mostly 
10 inches in diameter. The casing extends from 52 to 103 feet. 
The elevation above sea varies from 8 to 15^4 feet. The water 
in these wells will rise 15 to 17 feet above sea level, hence most 
of the wells flow at the surface. The following is a log of one 
of the wells taken from the Second Annual Report of this Survey, 
page 89: 
Feet. 
White Pleistocene sand . 0- 2 
Tough yellow clay with no sand, residual clay. 2- 12 
Soft limestone, which disintegrates readily, “Tampa lime¬ 
stone” ... 12- 26 
Chert, “Tampa silex bed”. 26- 30 
Soft limestone, closely resembling that at 12 to 26 feet.... 30- 36 
Tough, plastic, greenish sandy clay. 36- 77 
Base of the Tampa formation: 
Chert . 77- 79 
White’ marl . 79- 85 
Soft limestone ... 85- 90 
Very light colored hard rock . 90-105 
Very hard dark yellow limestone. 105-111 
Gray, porous limestone with some water. 111-126 
Cherty beds . 126-140 
Darker limestone. 
Gray plastic clay. 
Hard yellow rock with chert. 
Gray, porous rock, water-bearing. 
Like preceding. 
