TO GEOLOGY. 117 



small round mouth which is much thickened and reflected. 

 The ribs have some resemblance to the multistriata (Say), 

 a recent species of our southern coasts, but it certainly is not 

 the same species. 



In England the Scalariw have not been found below 

 the London Clay. Five have been described from that 

 formation, and six from the Crag. The Tables of M. 

 Deshayes give twenty-two species from the three periods 

 of the Tertiary, which seem there to be nearly equally 

 distributed. In the Cretaceous Group of New Jersey, Dr 

 Morton discovered a fine species (annulata). Mr Conrad 

 mentions two as existing in the Tertiary of Maryland. 



GENUS DELPH1NULA. Lamarck. 



D. plana. Plate 4. Fig. 104. 



Description. Shell subdiscoidal, carinate, beneath flat, 

 obsoletely and transversely striate, above rounded and 

 strongly striate ; substance of the shell rather thin ; spire 

 flattened ; suture widely furrowed ; umbilicus wide, cari- 

 nate, striate ; whorls four ; mouth oblique, round within, 

 subangular at the outer edge. 



Length .1, Breadth .2, of an inch. 



Observations. This little species is remarkable for the 

 flatness of its inferior portion, for its carina, and wide fur- 

 rowed suture. Between the transverse striee and in the 



