220 
FLORIDA STATE GEOLOGICAL SURVEY. 
described in much detail by E. O. Hovey. 1 From them Hovey con¬ 
cluded that the Pleistocene rock at Key West was but twenty-five to 
fifty feet thick. There can be no question as to the accuracy of Dr. 
Hovey’s description, but it seems doubtful whether the samples were 
taken and labeled with equal accuracy. Hence the evidence of the 
samples is not conclusive. East of Key West no section of greater 
depth can be had than those of the excavations along the line of the 
Florida East Coast Railway, and from none of these was material taken 
at a greater depth than ten feet below sea level except in some of the 
crossings between the keys where the maximum depth may have been 
more. So far as the writer knows, all of the material shot up between 
Big Pine Key and Key West was oolitic. A well at Big Pine Key 
went through the oolite; the exact thickness there is uncertain, but is 
probably less than fifty feet 
Physiographic Expression: — As the Key West oolite covers the 
islands west of Bahia Honda Channel to Key West, the distribution 
of the outcrops is quite different from that of the Key Largo lime¬ 
stone, the islands west of Bahia Honda lying in an irregularly tri¬ 
angular archipelago instead of a long thin line. The relief of these 
islands is nowhere fifteen feet, the highest land on the largest of the 
islands, Big Pine, is but thirteen feet above tide, as is the highest 
ground on Key West. On many of the keys between Big Pine Key 
and Key West bed rock barely reaches to sea level, the islands being 
low-lying flats of marl with many patches of mangrove swamp that 
are inundated to a depth of five feet during hurricanes. 
Like the Miami oolite the Key West oolite weathers easily, but its 
surface nowhere has the rough and jagged appearance of the rock 
in the Biscayne pineland. While roots have disrupted angular blocks 
the surface in general is smooth and over many areas as extensive as 
100 square yards shows no sign of roughening by decay. 
Small vertical holes of varying size and shallow hollows charac¬ 
terize the outcrops. The holes communicate frequently with under¬ 
ground water channels which often are larger than those found in 
the Key Largo limestone. In places these passages contain salt water 
a quarter of a mile or more from the shore line, and must be com¬ 
paratively free openings of considerable extent. 
Paleontologic Characteristics: — The abundant marine fossils in 
the Key West oolite comprise remains of corals, echinoderms and 
mollusks, with foraminifera and other less evident fossils. Collec¬ 
tions made by T. Wayland Vaughan on Torch Key and by the writer 
on Big Pine Key, give, according to Dr. Vaughan, a total of twenty- 
1 Hovey, E. O. Notes on the Artesian well sunk at Key West, Florida, in 
1895 . Mus. Comp. Zool., Bull. XXXVIII, 65 - 91 , 1896 - 
