SECOND ANNUAL REPORT-SOUTHERN FEORIDA. 219 
pared it to recent deposits along the keys and in 1852, L. Agassiz, 1 
described the rock in some detail. Hunt believed that the oolite had 
formed from the consolidation of limy material similar to that ac¬ 
cumulating about the keys; while. A. Agassiz thought that the Key 
West, like the Miami oolite, had an aeolian origin. All the oolite out¬ 
cropping on the keys south of Florida Bay is here designated the Key 
West oolite. 
Stratigraphic Position:—On the south side of Big Pine Key and 
on one of the New Found Harbor Keys the Key West oolite appar¬ 
ently overlies the Key Largo limestone. Its relation to the non- 
oolitic rock called in this paper the Lostmans River limestone cannot 
at present be determined, since the contact or, possibly, line of grada¬ 
tion between the two lies under the Bay of Florida. The oolite is 
overlain by recent marls and calcareous sands and in places along the 
shores of the keys may have a thin veneer of beach rock. 
Lithologic Characteristics'Typically the Key West oolite is a 
soft white or light-colored fossiliferous oolitic limestone, the ovules 
being scattered through amorphous carbonate of lime or surrounded 
by a crystalline cement that develops most freely along bedding planes. 
The ovules on the average have a longest diameter of about ^4 mm. 
The rock is less sandy than the Miami oolite, but resembles the latter 
in general appearance and physical qualities, there being little differ¬ 
ence between hand specimens of the two. 
Like the Key Largo limestone, the Key West oolite shows on many 
unweathered exposures a thin, dark crust, finely banded, of more or 
less amorphous carbonate of lime. In this crust all traces of oolitic 
structure disappear. The rock frequently shows cross bedding, but 
not so conspicuously as does the Miami oolite. It is easily quarried 
and dressed; makes a fair building stone and good road metal. 
Under the microscope the oolitic ovules of the Key West rock re¬ 
semble those of the Miami rock. The nuclei of the ovules are mostly 
rounded calcareous grains; occasionally a grain of quartz is a nucleus. 
The general appearance of the ovules indicates a formation in uncon¬ 
solidated material in the presence of water. 
Thickness: — The maximum thickness of the oolite is unknown. 
Several wells over fifty feet deep have been sunk at Key West, but 
from only two of these were samples preserved. A well sunk near the 
plant of the Consumers Ice Company, according to the driller, pene¬ 
trated sixty-five feet of rock of the same general character as that at the 
surface. Samples from the deep well in Jackson Square have been 
1 Agassiz, L,., op. cit, pp. 145-160. 
