BULLETIN 90, UNITED STATES NATIONAL MUSEUM. 



yielded 128 species unknown to science, which were described and 

 figured in the Transactions of the Wagner Institute/ together with 

 other Floridian fossils. 



In the Neocene volume the information in regard to the relations 

 of the silex beds and associated strata, gathered through five years' 

 investigations in various parts of the peninsula, were correlated and 

 the whole subject reviewed. It was shown that the so-called Miocene 

 of Florida was divisible into two groups separated not only by a 

 marked change in the character of the deposit, but by a surprisingly 

 sharp distinction in the character of the faunas, the essentially sub- 

 tropical fauna of the lower group being replaced in the upper one 

 by a fauna characteristic of much colder water. These two groups 

 were tentatively considered under the terms Older and Newer Mio- 

 cene, respectively, and the various zones or horizons disposed as in 

 the following table.- The colloquial term " Silex bed " was replaced 

 by the name " Orthaulax bed" from the most characteristic fossil. 

 The superincumbent limestone was named the "Tampa limestone," 

 and the series of beds above the lower part of the Chattahoochee 

 limestone of Langdon and including the Alum Bluff beds ^ Avas asso- 

 ciated under the designation of the " Tampa Group." 



TaUe of 1892. 

 [The horizons arc arranged in ascending order fion the lower line.] 



Cold Water fauna. Newer Miocene 



Chesapeake Group. Ecphora bed (Alum Bluff.) 

 Warm Water fauna. Older Miocene. 



Alum Bluff beds. -fSands and clays. 



[Chert of Hillsboro' River. 

 [Tampa limestone. 

 ? ' ' Infusorial earth . ' ' 

 White Beach sand rock. 

 Sopchoppy limestone. 

 Chipola marls. 

 .Orthaulax bed. 



!? "Cerithium rock" Tampa. 

 Chattahoochee limestone. 

 Water bearing sands. 

 (Phosphatic oolite. 

 Ferruginous gravels. 

 Greenish clays. 



A more thorough study of the fauna led to the recognition of the 

 correlation of the above-mentioned " Older Miocene," including the 



1 Trans Wagner Inst., vol. 3, 1890-1903. 



^ Bull. U. S. Geol. Survey, No. 84, 1892. 



3 Afterwards proved to include the local equivalent of the Oak Grove sands. 



Tampa Group. 



Tampa beds. 



Chipola beds. 



Ocheesee beds. 



Chattahoochee Group. 



