NEW AXD LITTLE-KNOAVX AVAVERLY FOSSILS. 47 



convexity greatest a little in front of the beak, the region from that point to 

 the front elevated ; surface marked by relatively strong concentric ribs ; 

 structure of shell unknown ; lower valve flat or slightly concave. 



Our specimens are all casts, and none of them preserve the structure of 

 the lower valve. There is no species with which it could be confounded. 

 Dimensions of one individual : length, 52 mm. ; width, 50 mm. ; beak from 

 front, 11 mm.; of a second individual, 50 mm., 46 mm. and 11 mm.; and of 

 a third, 48 mm., 47 mm. and 11 mm.^^ 



* Bulletin Denison University, vol. V, 1880, p. 28. 



VII— Bum,. Gkoi, Sue. Am., Voi.. 2, IS!)0. 



