S82 CRETACEOUS PALEONTOLOGY. 



Cardium lorillardensis n. sp. 

 Plate LXIV., Figs. 5-6. 



Description. — The dimensions of the internal cast of a left 

 valve are : height, 30 mm. ; width, 25 mm. ; convexity, 10 mm. 

 Shell oblique, subovate to subrhomboidal in outline. Hinge-line 

 nearly straight; anterior and basal margins curving with a 

 gradually decreasing curvature from the anterior cardinal ex- 

 tremity nearly to the postero-basal extremity; postero-basal ex- 

 tremity more sharply rounded ; posterior margin obliquely trun- 

 cate, -a little convex above and below, straight or nearly straight 

 in the middle. Beaks situated at about the middle of the hinge- 

 line, prominent, elevated above the hinge-line, acute, incurved, 

 pointing anteriorly. Valves with a subangular umbonal promi- 

 nence or ridge extending from the beak obliquely backward to 

 the postero-basal extremity ; anterior slope long and nearly regu- 

 larly convex, posterior slope abrupt, usually a little concave. 

 Surface of shell marked by about 40 or 45 angular radiating 

 costse a little narrower than the intervening furrows, and by very 

 fine, concentric, sublamellose lines which are much more con- 

 spicuous upon the anterior faces of the radiating costs. 



Remarks. — This species can be easily distinguishfed from any 

 other member of the genus in the New Jersey Cretaceous faunas, 

 by reason of its subangular umbonal ridge, its obliquely truncate 

 posterior margin, and by the peculiarity of the fine, concentric, 

 sublamellose lines upon the surface being much more conspicuous 

 upon the anterior faces of the costae. 



Formation and locality. — Woodbury clay, Lorillard (102). 



Geographic distribution. — New Jersey. 



Cardium ripleyanum Conrad. 



Plate LXV., Figs. 4-6. 



1869. Cardium ripleyanum Con., Am. Jour. Conch., vol. 5, p. 



96, pi. 9, fig. 6. 

 1886. Cardium ripleyanum Whitf., Pal. N. J., vol. i (Monog. 



U. S. G. S., vol. 9,) p. 132, pi. 20, fig. 14. 



