236 PALEONTOLOGY OF NEW JEESEY. 



Eocene beds, and is situated nearer to the anterior end of the shell than in 

 that species, showing the obliquity of the body of the shell to be its normal 

 condition, and proving its specific distinction. The different elements of the 

 hinge have much the same characters and proportion to each other as have 

 those of C, alta^ but the plate is higher from the inner margin to the apex 

 of the beak in proportion to the antero-posterior diameter. This feature, 

 with the fact that a much larger part of the body of the valve is posterior 

 to the central line of the hinge-plate, will readily serve to distinguish the 

 species from that one if it should ever be found with the shell preserved. 



Formation and locality, — The only examples which I have seen have 

 been from the top layers of the Upper Marl Beds at Shark River, New 

 Jersey. 



CARDIID^, 



Genus PEOTOCAEDIUM Beyr. 



Protocardium curtum. 

 Plate XXX, Figs. 5-7. 



Protocardia curta Conrad. Am. Jour. Conch., 1870, Vol. V, p. 42, PI. I, Fig. 1. Meek, 

 Check-list, p. 731. (Antedated, descrijjtion first published 1870.) 



Shell of medium size, subquadrangular in outHne, with nearly equi- 

 lateral and moderately convex valves. Beaks large, prominent, posterior 

 to the middle of the shell, and incurved ; cardinal line strongly arcuate, par- 

 allel to the basal line, and nearly equally curved, the basal line curving 

 abruptly upward at, and blending imperceptibly into the anterior end, this 

 latter being narrower than the posterior. Posterior margin abrupt, slightly 

 oblique, being just within a right angle with the postero-basal line. Um- 

 bonal angle sharply defined, and the posterior slope narrow and abrupt. 

 The surface of the shell has been marked throughout by fine, radiating 

 striae, of which seven or eight may be counted in the space of an eighth of 

 an inch on the margin of a specimen measuring nearly one and three- 

 fourths inches in height. On the posterior slope the striae are somewhat 

 coarser than on the body of the shell. The hinge, as seen on a very well- 

 preserved cast of a right valve, has been characterized by a strong lateral 



