46 CRETACEOUS GROUP 



I have much pleasure in dedicating this only known 

 American species of Nummulites, to one of the most ar- 

 dent and successful cultivators of geological science, 

 Gideon Mantell, Esq., of Brighton, England. 



GASTEROPODA. 

 Bulla. 



1. Casts not very unlike B. lignaria. From New 

 Jersey. 



2. A solitary cast of a large, ventricose species, was 

 found by Mr. Conrad in Alabama. 



Trochus. 



1. T. leprosus, (S. G. M.) pi. xv. fig. 6. 



Specific character. Compressed ; spire composed of about 

 four volutions, presenting an unequal, rugged surface. 



Diameter, from an inch to an inch and a half. 



From Prairie Bluff, Alabama. T. A. Conrad. 



This species has considerable resemblance to T. ag- 

 glutinans,, a recent shell of the West Indies. 



2. I have observed some casts of this genus in the cal- 

 careous strata of New Jersey. 



Delphinula. 



2. D. lapidosa, (S. G. M.) pi. xix,fig. 7. 



Specific character. Shell discoidal, with about three volu- 

 tions ; shoulder angulated ; margin flattened ; umbilicus pro- 

 foundly patulous ; spire slightly elevated above the body whorl. 



From Prairie Bluff, Alabama. 



