ADDITIONAL OBSERVATIONS 



JUNE, 1835. 



A further examination and comparison of the fossils of 

 the preceding Synopsis, has enabled me, with the assist- 

 ance of Mr. Conrad, to separate the Cretaceous deposits 

 of America into three great divisions, each possessing 

 common characters, together with others which are suffi- 

 ciently distinctive. For the sake of convenience, these 

 divisions may be called the Upper, Medial and Lower. 



The Upper Division embraces the Nummulite Lime- 

 stone of Alabama, (p. 22,) and the Cretaceous strata of 

 South Carolina, (p. 20.) Its characteristic fossils are, 

 Nummulites Mantelli, Terebratula lachryma, Pecten 

 membranosus, P. Poulsoni, Plagiostoma dumosum, Balanus 

 peregrinus, Nautilus Alabamensis, Scutella Rogersi, S. 

 Lyelli and Echinus infulatus. To this division Mr. Conard* 

 refers the gigantic remains of the Basilosaurus. [Harlan. ] 

 The Medial division is partially seen at Wilmington, 

 North Carolina, (p. 20,) and to a considerable extent in 

 New Jersey, (p. 16.) Its characteristic fossils are, Spa- 

 tangus parastatus, Nucleolites crucifer, Ananchytes fim- 

 briatus, Teredo tibialis, Scalaria annulata, Belemnites 

 ambiguus, and Vermetus rotula. It also contains the re- 

 mains of crocodiles and sharks. 



* Fossil Shells of the Tertiary Formation of N. America, p. 35. 



