W. E. D all— Geology of Florida. 165 



away leaving only patches, generally in depressions but occa- 

 sionally in short ridges. The appearance of the contained 

 bones suggests that the animals were mired and then torn to 

 pieces by predatory carnivora. Ashes and burnt clay were 

 found under some of the bones at Hallowell's ranche but there 

 was no evidence of any human agency in this. The fire was 

 probably due to lightning, an every-day occurrence in Florida 

 at the present time. The longitudinal splitting of the long 

 bones sometimes observed, may often be the result of the pen- 

 etration, and growth in the hollow of the bone, of roots, which 

 might afterwards decay and leave no sign. I have observed 

 roots penetrating the bones on several occasions." These bones 

 are distributed over the State in many localities, especially in 

 Alachua County. 



The older rocks of course come out to the northward and 

 along the central part of the peninsula, and the succession of 

 the newer ones is toward the southern extreme end and the 

 Atlantic and Gulf shores. The hypothetical southward exten- 

 sion of the Oligocene (sometimes taken as Eocene) on most 

 recent geological maps now seems erroneous. It is without 

 doubt represented as considerably too great. 



Fossil iferous rocks have long been known to exist at Ballast 

 Point, Hillsboro' Bay, near Tampa, where they were observed 

 by Conrad more than 40 years ago. Eecently Prof. Heilprin 

 has examined them, referred them to the Miocene, and 

 described a number of interesting species. 



Here we find a state .of things which is largely repeated in 

 the younger strata to the southward. The rock rises but a few 

 feet above the beach. Two layers may be distinguished, es- 

 pecially by their fossils, for the rocks are so broken up that 

 the superposition of the newer layer here is less clear than 

 I found it farther inland. The older rock is composed of a 

 limestone, which in some places is so impregnated with silex as 

 to form an almost pure flint ; and at other spots retains its 

 limy character, or is decomposed into a marl of peculiar ten- 

 acity. In many places the marl occurs in pockets surrounded 

 by or covered with chert. In other spots it forms the greater 

 part of the bank; but, however different in character, the chert 

 and marl are merely parts of one stratum which has been sub- 

 jected to different processes of mineralization in its different 

 parts, and not two strata or rocks. In the chert the fossils, of 

 which the rock is full, have disappeared, leaving cavities from 

 which their forms may be reproduced by moulding in gutta 

 percha. In the marl they have also disappeared but the 

 smaller ones are represented by more or less perfect pseudo- 

 morphs of subtranslucent silex, reproducing every detail of 

 the original shell. The larger ones, such as heads of coral, re- 



