36 CRETACEOUS GROUP 



Nevertheless I am by no means certain that this fossil is 

 a Belemnite, and Mr. Mantell has examined it without 

 coming to a decision. 



From the calcareous strata of New Jersey, especially 

 on Timber creek, Gloucester county. 



M. de Blainville makes the following remarks on the 

 Geological position of Belemnites : 



" Jusqu ? ici, leur presence est presque characteristique 

 des terrains secondaires, ou des formations qui se trouvent 

 entre les terrains intermediates, et les terrains tertiaires 

 superieurs a la Craie. Je ne connais, en effet, presque 

 aucun auteur qui indique les Belemnites veritables dans 

 les differens strates du terrain de transition, non plus que 

 dans les terrains de sediment superieurs a la craie. "* 



The author then states, on the authority of Mr. Under- 

 wood, that Belemnites have never been found in the Lon- 

 don clay, as some have asserted. Conybeare and Phillips 

 make a similar observation. 



AMMONITES. 



1. A. placenta, (Dekay,) pi. ii. fig. 1, 2. 



Ann. N. York Lye. Nat. Hist. vol. ii. pi. v. fig. 2 ; Journ. 



Acad. Nat. Science, vol. vi. pp. 88, 112, 195; Am. Journ. 



Science, vol. xviii. pi. ii. fig. 1, 2, 3. 



. Specific character. Discoidal, with three or four broad, 



compressed whorls, tapering towards each edge ; one half the 



whorl being embraced and concealed by the contiguous one ; 



inner whorls having slight transverse elevations, tuberculated 



at their inner margins ; septae on the surface, numerous, multi- 



lobed, sigmoid. 



* Memoirs sur les Belemnites, p. 48. 



