TO GEOLOGY. 165 



older Pliocene, Maryland, and Mr Conrad two from York 

 Town, Virginia, also the older Pliocene. 



GENUS NASSA. Lamarck. 



JV. cancellata. Plate 5. Fig. 170. 



Description. Shell turrited, cancellate ; substance of 

 the shell rather thin ; spire elevated, not acutely pointed ; 

 suture irregularly impressed ; whorls nine, subangular 

 above and furnished with a transverse furrow ; mouth 

 ovate ; columella but slightly thickened ; outer lip sub- 

 crenate, striate within. 



Length .8, Breadth 7-20ths, of an inch. 



Observations. This finely ornamented Nassa has a 

 strong resemblance to several recent species. It is can 

 cellate all over except at the very apex, where it is smooth 

 and polished. 



I have observed but a single species of this genus among 

 the shells received from Claiborne. I have not hesitated 

 to separate this genus from Buccinum, (although Lamarck 

 united them after having made the division) because they 

 certainly form a very natural group. Cuvier* separates 

 it, as M. de Blainvillef also does, into a subgenus. 



As neither the English nor French geologists have 



* Animal Kingdom, vol. 2, p, 374. t Manuel, &c. p. 408. 



