TO GEOLOGY. 59 



recurved ; cardinal and lateral teetli rounded ; cicatrices 

 not deeply impressed; the lines of growth numerous and 

 deeply furrowed, causing a crescent like appearance ; cavity 

 of the shell deep of the beaks deep and rounded, having 

 no visible furrow ; margin crenulate. 



Diam. .2, Length .3, Breadth .2, of an inch. 



Observations. Differs from impressa in size, obliquity, 

 striae, and the deeply seated lunule. 



Seven species have been noticed in the strata of Great 

 Britain, from the Great Oolite to the Crag one only in 

 the London Clay. In M. Deshayes s valuable Tertiary 

 Tables we find fifty-nine, of which thirty-one are from the 

 Paris basin (Eocene). Twelve are from Bourdeaux (Mi 

 ocene). Mr Say has observed five in the Tertiary of 

 Maryland, and Mr Conrad two from the Tertiary of Clai- 

 borne. 



GENUS GRATELUPIA. Des Moulins. 



G. Moulinsii. Plate 2. Fig. 33. 



Description. Shell subtriangular, inflated, gibbous over 

 the umbo, very finely and transversely striate, nearly equi 

 lateral ; obtusely angular behind, subemarginate on pos 

 terior basal margin ; lunule large and lanceolate ; margin 

 entire. 



Diam. 1, Length 1.4, Breadth 1.9, of an inch. 



