Mesozoic and Ccenozoic Geology and F aloe ontology. 11 



masses of chert, and also present some appearances of the green grains 

 so characteristic of the adjacent marls. 



The Cretaceous formation is unequivocally recognized in New- 

 Jersey, from whence it nay be locally traced through Delaware, Mary- 

 land, Virginia, North and South Carolina, Alabama, Mississippi, Ten- 

 nessee, Louisiana, Arkansas and Missouri, it is also, probabl}^ traced 

 to Long Island, and probabl}^ forms the substratum of the islands of 

 Nantucket and Martha's Vinej'ard. "These various deposits", he 

 sa3^s, "though seemingly insulated, are doubtless continuous, or nearl}^ 

 so, forming an irregular crescent, nearly 3,000 miles in extent; and 

 there is not only a generic accordance between the fossil shells scat- 

 tered through this vast tract, but in by far the greater number of 

 comparisons I have hitherto bpen able to make, the same species of 

 fossils are found throughout: thus, the Ammonites placenta., BacuUtes 

 ovaius, Gryphcea vomer, G. mutabiUs, and Ostrea falcata, are found 

 without a shadow of difference from New Jersey to Louisiana; although 

 some species have been found in the latter State that have not been 

 noticed in the former, and vice versa.'" 



The calcareous strata appear to be much less extensively distribut- 

 ed than the friable marls, and present considerable difference in their 

 organic characters, and alwaj's when observed form the overljnng beds 

 of this formation. 



Two sections of the strata, as observed in Delaware, are furnished. 

 Localities of exposure are mentioned in Maryland, Virginia, North and 

 South Carolina, Georgia, Alabama, Mississippi, Tennessee, Louisiana, 

 Arkansas, Missouri, and in the level countrj^ between the Missouri river 

 and the Rocky Mountains. 



He described: Nautilus dekayi, Ammonites navictilaris, A. pet- 

 echialis, A. telifer, A. conradi, now Scaphites conradi, A. conradi, var. 

 gulosus, now Scaphites conradi, var. gulosus, Scaphites reniformis, A. 

 vesper tinus., now 3Iortoniceras vespertinum, A. syrtalis, now Placenti- 

 ceras syrtalis, BacuUtes asper, B. carinatus, B. columna, B. labyrin- 

 thicics, Hamites arculus, Hz torquatus, H. traheatus., Trochus leprosiis, 

 now Phorus leprosus, Delphinula lapidosa, now Angaria lapidosa. 

 TurriteUa encrinoides, T. vertebroides, Scalar ia sillimarii, S. annulata, 

 Rostellaria pennata, IN atica abyss ina, now Gyrodes abyssina, JST. 

 petrosa, now G. petrosus, Cirrus crotaloides. Patella tentorium, Ostrea 

 cretacea, 0. plumosa, Pecten craticula, Placuna scabra^ Inoceramus 

 barabi7ii, I. alveatus, Avicula laripes, Pectunculus australis, now 

 Axincea australis, P. ham'ula, now A. hamula, Area rostellata, now 

 Cibota rostellata, Cucullcea antrosa^ now Idonearca antrosa, V. vul- 



