644 CRETACEOUS PALEONTOLOGY. 



Corbula jerseyensis n. sp. 



Plate LXXIL, Figs. 37-38. 



Description. — The dimensions of a perfect internal cast are: 

 length, 6 mm. ; height, 4 mm. ; thickness, 3 mm. The dimen- 

 sions of a larger left valve are : length, 9 mm. ; height, 6 mm. 

 Shell ovate-subcuneate in otitline, the ventral margin of the right 

 valve overlapping the left; beaks subcentral, pointing slightly 

 forward, that of the right valve a little more elevated and sharper 

 in the cast than that of the left. Hinge-line arcuate; anterior 

 and posterior cardinal margins sloping symmetrically from the 

 beak, where they meet in an angle of about 120° ; anterior mar- 

 gin regularly rounded; ventral margin gently convex; postero- 

 basal extremity angular; posterior margin truncate below, sub- 

 angular above or curving into the postero-cardinal margin. 

 Valves gently convex in their central portion, the surface curving- 

 abruptly to the antero-cardinal border; posteriorly an angular 

 umbonal ridge separates the body of the shell from the post- 

 umbonal slope; post-umbonal slope short, abrupt, concave. Sur- 

 face of the shell nearly smooth, marked only by fine, inconspicu- 

 ous lines of growth which become a little more prominent on the 

 post-umbonal slope. In the cast the angular umbonal ridge of 

 the exterior of the shell is nearly or quite obsolete, and the mus- 

 cular impressions are inconspicuous. ■ 



Formation and locality. — Cliffwood clay, Cliffwood Point 

 (185). 



Geographic distribution. — New Jersey. 



Corbula swedesboroensis n. sp. 



Plate LXXII., Figs. 33-36. 



Description. — The dimensions of a nearly perfect right valve 

 are: length, 12.5 mm.; height, 9 mm.; convexity, 3.5 mm.; a 

 larger imperfect valve is 15 mm. in length. Shell subovate in 

 outline; the beak in front of the middle, rather small, a little 

 incurved, pointing forward. Anterior and posterior cardinal 

 margins meeting at the beak in an angle of about 133°; anterior 



