Wi anaeeh 
66 CRETACEOUS GROUP 
CARDIUM. 
1. Casts of a smooth species are common in all the 
strata: they vary in size from half an inch to an inch in 
length. 
2.? Larger, ventricose casts, strongly ribbed. 
CARDITA. 
C. decisa, (S.G. M.) PI. ix, fig. 3. 
Specific character. Subtriangular, ventricose, longitudinally 
striated and transversely undulated ; posterior end truncated ; 
margin straight. 
From the blue marl of St. Georges, Delaware. 
I am not positive that this cast is from a Carditas but 
it most resembles this genus, and is unlike any other marl 
fossil with which I am acquainted. 
CRASSATELLA. 
C. vadosa, (S.G.M.) PI. xin, fig. 12. 
Specific character. Ovato-triangular, slightly compressed ; 
with about thirty distinct, concentric strie. 
Length, one inch and a quarter; breadth, one inch. 
From the older cretaceous strata at Prairie Bluff, Ala- 
bama. Mr. T. A. Conrad. Casts of this genus are not 
uncommon in New Jersey. It is probable that the black- 
ish ones so common in the neighborhood of Long Branch, 
belong to Crassatella. Mr. Vanuxem has spoken of them 
as Mytil, in which I followed him; but there can be no 
doubt of this being a mistake. 

