46 
FLORIDA STATE GEOLOGICAL SURVEY. 
of the Miocene waters which are assumed to have covered this 
section of the State. While submerged there was deposited upon 
the limestone, according to Wyatt, more especially in the cracks 
and fissures, a soft, finely disintegrated calcareous sediment or 
mud. As the seas dried up estuaries were formed in which were 
found great numbers of fish, mollusks, reptiles and marine plants. 
The formation of the phosphate is attributed to the reactions 
between the calcareous sediments and the decaying animal and 
plant life. 
Professor E. T. Cox, in a paper read before the Indianapolis 
meeting of the American Association for the Advancement of 
Science, August, 1890, expresses the view that the hard rock 
phosphates of Florida are derived from the mineralization of an 
ancient guano. His argument is that as the peninsula of Florida 
was elevated above the ocean the land bordering the sea on the 
west coast became the resting place for numerous aquatic birds 
and other animals. The humid character of the climate caused 
the soluble alkalies to be removed, leaving the less soluble phos¬ 
phate of lime. This accumulation of guano subsequently became 
mineralized, thus resulting in the hard rock phosphates. This 
theory is restated in papers subsequently published by Cox in 
1892 and 1896. 
Professor Cox mentions two other views current at that time. 
These are stated as follows: “It is a well known fact that phos¬ 
phorous is an element and, like the element of iron, is almost 
universally distributed over the globe, and is found in all the living 
things thereon. Therefore, it is reasoned that it may, like iron, 
be accumulated in large beds by a natural law which governs the 
concentration of mineral masses. Again, it is suggested that phos¬ 
phoric acid, derived from mollusca, deposits from birds, fish and 
saurians, has filtered down and replaced the carbonic acid in the 
underlying limestone, converting it into phosphate of lime.” To 
the first of these suggestions Cox offers no objection. Of the 
second, however, he says, “Against the latter theory the phos¬ 
phate of lime very rarely contains any trace of organic remains, 
while the limestone on which it rests is rich in the casts of mollusca 
that are referred to the Eocene age. Then, again, in proximity to 
