OF THE UNITED STATES. 4] 
it is accompanied by GrypH@a vomer, G. Pitcheri and 
Exocyra costata. It is allied to A. Delawarensis, but 
differs in the absence of bifurcations in the coste. 
ScapPuirTes, Parkinson. 
S Cubieri 3. G. M. §Ph vibig. 1 
Ammonites hippocrepis, (Dekay.) 
Annals of the New York Lyceum, vol. ii. pl. v. fig. 5. 
Specific character. Larger whorl ventricose, with eight pro- 
minent lateral tubercles, and two others more elevated at the 
inner margin on each side; back delicately ribbed between 
the lateral tubercles; an obscure ridge from each of the latter 
to the umbilical margin ; no visible septa: smaller whorl com- 
pressed, half concealed, costated all round; septa numerous, 
serrated like those of an Ammonite.* 
Diameter of larger whorl, an inch and a half. 
Diameter of smaller whorl, an inch and an eighth. 
This beautiful specimen is a black sub-siliceous cast: 
it was found about sixty feet below the surface, at the 
deep cut of the Chesapeake and Delaware canal, in an 
argillo-ferruginous sand. 
This fossil was obligingly presented to me by my friend 
Mr. Wm. L. Newbold, to whom I am under many simi- 
lar obligations. 
Dr. Dekay first described this fossil from an imperfect 
fragment, and called it AmmMonirss hippocrepis. Seve- 
ral years afterwards, I satisfied Dr. Dekay that we had 
*S. anfraciu majori yentricoso, tuberculis octo in utroque latere, cum duobus 
alteris prope marginem internam; dorso pulehre costato inter tuberculas: an- 
fractu minori compresso, costato, semi occultato; septis serratis. 
EF 
