PETROLEUM POSSIBILITIES OE FLORIDA 
101 
formation comes into the section. A number of water wells have been 
drilled in this county, although none of them exceed 400 or 50(1 feet in 
depth. No logs of these wells are available. However, it is probable 
that after passing through the sands and clays of the Alum Bluff forma¬ 
tion, Eocene and probably older limestones are encountered. The dip 
of the Eocene limestones in Columbia County is probably to the north 
or northeast, as the county lies on the east of the Live Oak dome and on 
the north flank of the central Florida uplift. 
DADE COUNTY 
Dade County is on the Atlantic coast of southern Florida. The sur¬ 
face formations in this county are Pleistocene and include oolitic lime¬ 
stones and shell marls. The thickness of the Pleistocene in wells in this 
county has not been recorded. Deep wells have been drilled at Miami 
Beach, a log of which follows. It is possible that the Eocene forma¬ 
tions lie as much as 1,000 feet or more below the surface in the eastern 
part of this county: 
Composite log of two wells drilled at Miami Beach, Dade County. Log received 
from, and used by permission of, United States Geological Survey. 
Sand and shell . 
Black muck .... 
First rock .. 
Quicksand and water ___ 
Lithia lime —. 
Quicksand .... 
Coquina rock ... 
Soft sand .... 
Soft sand, rock . 
Lime shell .. 
Soft rock .. 
Lime shell . 
Gray coquina rock . 
Hard lime and shell. 
Soft, yellow coquina . 
Lime shell .. 
Soft coquina .. 
Blue mud ... 
Coquina rock ... 
Quicksand ... 
Soft sand rock ...,. 
Soft sand, with streaks of blue marl 
Greenish clay ..... 
Soft sand rock ... 
Blue clay ... 
lickness. 
Depth. 
5 
0- 5 
2 
5- 7 
2 
7- 9 
12 
9- 21 
12 
21- 33 
30 
33- 63 
20 
63- 83 
14 
83- 97 
30 
97- 127 
2 
127- 129 
23 
129- 152 
2 
152- 154 
18 
154- 172 
5 
172- 177 
30 
177- 207 
2 
207- 209 
21 
209- 230 
2 
230- 232 
30 
232- 262 
3 
262- 265 
300 
265- 565 
200 
565- 765 
5 
765- 770 
20 
770- 790 
5 
790- 795 
