Sand Formation of the United States. 281 



emy, several other specimens have been found, all precisely similar 

 to each other. In England and France this genus is characteristic 

 of the ferruginous sand. 



BELEMNITES. 



1. B. americanus. (S. G. M.) Allied to B. mucronatus of Eu- 

 rope. {Vide Blainville, Mem. sur les Belemnites, pi. 1. fig. 12. and 

 Sowerby, pi. 600. figs. 1, 2, 4, 6, and 7.) Abundant in the blue marls 

 in many parts of New Jersey. I have no question that some hun- 

 dreds might be collected in the compass of a few cubic feet. In a 

 paper printed in the Journal of Academy two years since, I referred 

 this species to Lamarck's B. subconiciis, chiefly, however, from an un- 

 willingness to multiply specific names. The subsequent examination 

 of numerous specimens, and the comparison of them with the de- 

 scriptions and figures in Blainville, Sowerby, &c. have convinced me 

 that the American belemnites require particular scrutiny. I there- 

 fore propose to give descriptions and accurate drawings of them, in 

 an early number of the American Journal of Science. 



2. B. ambiguus. (S. G. M.) This remarkable fossil is common 

 in the calcareous beds of Gloucester county, N. J. and has an anal- 

 ogue in B. cylindricus, (Blainville,) as figured by that author, pi. 3, 

 fig. 10, 10 a. It will be described and figured with the B. ameri- 

 canus. 



SIMPLE AND SPIRAL UNIVALVES. 



DENTALIUM. 



Casts of a pretty large species are found at Mullica Hill, N. J. and 

 at the Chesapeake and Delaware canal. 



TURRITELLA. 



1 . A large species with about five convolutions, is common through- 

 out this formation. It exists only in casts. 



2. Casts of a smaller species are frequent at the Deep Cut of the 

 Chesapeake and Delaware canal, in a matrix of dark clay and scales 

 of mica. 



SCALLARIA ? 



This beautiful shell is in perfect preservation excepting the mouth ; 

 hence the difliculty of deciding the genus. It has four volutions, 

 with numerous acute, longitudinal costEe, which are transversely stri- 

 ated. Length about an inch and a quarter. It is found in the cal- 



VoL. XVII.— No. 2. 9 



