284 Organie Remains of the Ferruginous 
exoe¥ra. Say.* 
E. costata. (Say.) This fossil is equally abundant with those last 
described, and is found in the ferruginous sand from New Jersey to 
South Carolina. Mr. Say is certainly correct in making a. distinct 
genus of this fossil, in proof of which it will be found that Mr, Sow- 
erby has placed a congeneric shell with Chama, (C. conica) while 
Mr. Brongniart classes another with Gryphea. (G. auricularis.t) 
The true Exogyra has but a single muscular impression in each valve, 
which sufficiently distinguishes it from Chama, while it differs still 
more strongly from Gryphea. It is an interesting fact that all those 
European fossils which belong to the genus Exogyra have been found 
exclusiyely in acknowledged secondary deposits. Thus the Chama 
conica and C. haliotoidea of Sowerby are peculiar to the green sand 
of England, while the Gryphea auricularis of Brongniart has been 
found, in E reece, only in chalk marl. 
-ostREA. Lam. 
: 0. tla (S. G.M.) This handsome species is about an 
inch and a half long, thin, curved, and plicated longitudinally from 
the hinge margin to the point. It is abundant at St. George’s, in 
Delaware, and is also found in many parts of New Jersey. 
_ 2. O. cristagalli? . I found a few valyes. at St. George’s, which 
have so much resemblance to this species, that I shall for the present 
adopt the name. The O. oristagalh is a. well known. fossil of the 
English chalk 
Or 1s hs bys. Ae i obtained at Mullica Hill, in N. J. a solitary 
inferior valve of an ostrea which differs from any I have seen. It 1s 
five inches long, seers costated, and replaced, with true flint-t 
er Or My friend Mr. T. A. Conrad has lately pre- 
shat me with a single valve, very-convex, with ten or twelve deep 
Piestions. It is entirely. different from any of the preceding species; 
Anomia, 
ba ? (Lam.) Iris extremely difficult to distinguish be- 
tween the recent and fossil — for which reason, for the get 
Fy : Amer. Jou. Science, Vol. I. 
t In the ts Age “agp ds Bn. Pai, F pak “8 am.) as a marl 
(Lam 
fossil. The specimens, however, were subse tertiary 
: quently found to be from the te 
deposit of Maryland. 
Sa ee 
