88 
FLORIDA GEOLOGICAL SURVEY-I 4 TH ANNUAL REPORT 
Depth in feet. 
pebble in the light-colored marl giving a grayish cast to the rock. The 
hard, blue rock that effervesces scarcely at all in acid is rather more 
abundant in this than in the preceding sample. This hard rock also 
contains black phosphate pebbles, and it is probable that it is merely 
a silicified phase of the marl. Some casts of fossils, but no determina¬ 
ble specimens. A considerable amount of clear-grained silicious sand 
is seen among the finer material..|. 85 
The material at this depth is also calcareous and phosphatic. The phos¬ 
phate pebbles are black or brown and are smooth and rounded. The 
rock contains numerous small cavities, giving it a porous appearance. 
Only one fossil is seen, this being part of a small gastropod.. 150 
A phosphatic limestone or marl, with some fossil gastropods and bi¬ 
valves preserved as casts. The rock at this depth is in general similar 
to the 150-foot sample. The fossils seem more abundant, perhaps, be¬ 
cause the sample is larger. The phosphate pebbles are black, brown, 
and white in color....sgJ.._.-..- 160 
Compact brown, phosphatic limestone. The phosphate pebbles are not 
abundant in this limestone and are in the form of small, black pebbles 
imbedded in the rock. While the rock is prevailingly compact, some 
porous fragments are seen. A few broken fossils preserved as casts... 180 
This sample includes compact phosphatic limestone, with about equal 
admixture of pure white, silicious sand. Whether the sand is from 
a sand stratum or from the six-inch cavity found at this depth, or pos¬ 
sibly accidentally mixed from the surface, is not known. 190 
A sandy, calcareous and phosphatic clay. In water this material falls 
to pieces and becomes liquid. In acid it effervesces. The sand is in 
the form of clear-grained silica. The phosphate is mostly in the form 
of small, black pebbles. Material is light colored when dry, although 
slightly bluish when wet............. 195 
This material is similar to that at 195 feet, although there is perhaps 
less phosphate, and the sand is perhaps smaller grained... 200 
A gray, sandy, phosphatic limestone. The calcareous material seems to 
predominate, although the rock is rather sandy. The sand grains are 
small and well rounded. The phosphate is in the form of very minute, 
dark specks, and the rock possibly also has a phosphatic cement. No 
fossils seen .......... 205 
A gray, sandy, phosphatic limestone. The calcareous material seems to 
predominate, although the rock is rather sandy, the sand grains are 
small and well rounded. The phosphate is in the form of very minute, 
dark specks, and the rock possibly also has a phosphatic cement. No 
fossils seen in this material, except some imperfect casts in fragments 
of a porous limestone, which may have fallen down from a higher 
stratum. These porous pieces occur also in the sample at 205 feet. 240 
Light-colored, sandy and phosphatic limestone. The sand grains are clear 
silica. The phosphate pebbles are dark colored. A few fragments 
of casts of fossils. This rock is not materially different from that at 
205 and 240 feet, except that it is lighter in color........ 250 
Bluish gray, sandy, phosphatic limestone, together with loose calcareous 
sand, probably representing the ground-up rock. No fossils seen ex¬ 
cept echinoderm spines......... 255 
Gray or blue, calcareous, sandy, phosphatic clay. No fossils. This ma¬ 
terial is similar to that at 200 feet. 255-260 
Bluish gray, sandy, phosphatic limestone, together with loose calcareous 
sand, probably representing the ground-up rock. No fossils seen ex¬ 
cept echinoderm spines........... 265 
