Sand Formation of the United States. 287 
ANANCHYTES. Lam. 
This genus is found in fine preservation in the calcareous deposits 
just mentioned. The species has much resemblance to one from the 
green sand of England in the collections of the Academy, but of 
which I do not know the specific name. The American specimens 
have five pair of ambulacra, one of which is contained in a deep sul- 
cus. Length from half an inch to an inch and three fourths. 
ecHINus. Lam. 
Of this genus I have hitherto found only pentagonal, oblong, de- 
tached plates; margin granulated, with a central, circular, smooth 
area, and a tubercle for the attachment of a spine. ‘These remains 
are well represented by the sections of the mammillated echinus, fig- 
ured by Parkinson, Vol. TI. pl. 1. fig. 11. 
CLYPEASTER. Lam. 
_ The blue marls have furnished a few casts of this genus. 
In the collection of the academy are some additional remains of 
Echinidea, but too imperfect to justify a classification, In the calea- 
teous beds of New Jersey, I found granulated echinal spines more 
than two inches in length, and not to be distinguished from those of 
the European chalk. I possess similar remains from the blue marls 
farther north. : : 
CRUSTACEA. 
astacus. Lam. iy 
_ Asmall species, but having nearly all its parts entire, was found 
m digging the Chesapeake and Delaware canal. 
cancer. Lan. ae 
Dr. Van Rensselaer* has described and figured four specimens 
(cheifly the claws) of this genus, from New Jersey. Three very 
distinct species are preserved in the academy, but these also are only 
the claws. From these scanty remains it would be almost impossi- 
ble to determine even the Lamarckian genera with any degree of ac- 
curacy. 
Portions of other crustacea have come under my observation, but 
Thave not yet been able to refer them to any definite place in the 
systems. 
ig aye 
* Annals N. Y. Lyceum, Vol. I. p. 195, &e. 
