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 intermediaires, 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,) pl. ii. fig. 1, 2. 
Ann. N. York Lyc. Nat. Hist. vol. ii. pl. v. fig. 2; Journ. 
Acad. Nat. Science, vol. vi. pp. 88, 112, 195; Am. Journ. 
Science, vol. xviii. pl. i. 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; septz on the surface, numerous, multi- 
lobed, sigmoid. 
* Memoire sur les Belemnites, p. 48. 
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