so Bulletin 15 360 



in the interior rest upon the limestone. At certain localities the 

 deposit is fossiliferous. 



Referred by Cotirad fa the Upper Eocene. In the same 3'ear,. 

 T. A. Conrad* visited the region and traced the limestone from 

 Fort Brooke to the Hillsboro and up the Manatee. He concluded 

 that the rock extends throughout the p>eninsula as far south at 

 least as Tampa Bay. He remarks that the fossils bear no resem- 

 blance to either Miocene or Eocene sp)ecies, but that the formation 

 will probably prove to be an upper member of the Eocene. Eight 

 species from the Tampa limestone at Ballast Point were described 

 hy Conradf a short time later. Among these is Bulimus flarida- 

 nus, which he notes as the first fossil land shell found in Ameri- 

 can Tertiaries. The other species are all marine, and include 

 Nummulites fioridanus , Bulla petrosa, Nucula tellinula, Cytherea 

 Horidana, Venus penita and V. fioridana. 



The basal layers of the Tampa limestone contain few fossiIs> 

 but, in the upper beds, Natica amphora and Vemis penita are said 

 by Dr. Dall to be very common. Lithodomus borings characflerize 

 the upper surface. 



Correlated with the Vicksburg formation. The occurrence of 

 the foraminifer described as Nummulites floridamis led Conrad to 

 correlate the Tampa with the Vicksburg limestone, since the 

 latter contained a species described by Morton as Nummulites 

 tnantelli, and was called the American Nummulitic formation. | 



Prof. Tuomeyll explored the Florida coast in 1850, and 

 agreed with Conrad that the limestone of Tampa and Fort Brooke 

 represents an older Tertiary deposit. 



The Coralline theory vf Agassiz and Le Conte. Disregarding 



*Obs. ou the Geol. of a part of E^st Florida, Ibid., vol. 2, pp. 36-48. 



t Descriptions of new species of organic remains from Upper Eiocene 

 Limestones of Tampa Bay, Ibid., vol, 2, pp. 399-400. 



X Both these generic determinations were later shown to be erroneous, 

 and Prof. Heilprin described the first true nummulite found in this country 

 in 1884. 



II Notice of the Geol. of the Florida Keys and the Southern Coast of 

 Florida, Amer. Jour. Set., 2nd ser., vol. 11, pp. 390 fE. 



