TO GEOLOGY. 131 



casts. Three species are described by Say and Conrad 

 from the Miocene of Maryland. 



FAMILY CANALIFERA. 



GENUS CERITHIUM1 Bruguiere. 

 C. striatum. Plate 4. Fig. 122. 



Description. Shell turrited, transversely and finely stri- 

 ate ; substance of the shell rather thin ; apex acute ; suture 

 not deeply impressed; whorls about thirteen, rather con- 

 vex; colurnella reflected; mouth subquadrangular, effuse 

 at base. 



Length 1 .3, B readth .4 , of an inch. 



Observations. The striae of this species have a strong si- 

 milarity to that of the Turritella lineata above described, but 

 the sutures are different. In most specimens numerous lon- 

 gitudinal flexed folds may be observed. 



I am by no means satisfied in placing this shell among 

 the Cerithia. It has a stronger resemblance in the mouth to 

 the genus Melania, but being a marine shell cannot with 

 propriety be placed in that genus. Blainville figures a shell 

 (plate 21, bis. fig. 2), under the name of Potamidesfragilis, 

 which certainly ought to belong to the same genus with this, 

 the mouth being very nearly the same. Until more species 

 shall be obtained, I have forborne to create for it a new 

 genus. More decisive characters may then be observed, 



