576 CRETACEOUS PALEONTOLOGY. 



Formation and locality. — Manasquan marl, Farmingdale 

 (Whitfield). 

 Geographic distribution. — New Jersey. 



Cardium wenonah n. sp. 



Plate LXIIL. Figs. 10-16. 



Description. — The dimensions of an average right valve are: 

 height, 12 mm.; w^idth, 12 mm.; convexity, 4 mm. Large in- 

 dividuals rarely attain a height of nearly 20 mm. Shell, exclu- 

 sive of the projecting beaks, subrhomboidal in outline. Hinge- 

 line nearly straight ; anterior margin rounded, most convex above 

 the middle, curving rather abruptly below into the gently convex 

 basal margin which is subparallel with the hinge-margin; pos- 

 tero-basal margin abruptly rounded; posterior margin gently 

 convex, slightly oblique, straighter than the anterior margin. 

 Beaks small, pointed, incurved, situated at about the middle of the 

 hinge-line and but little elevated above it. Along a line extend- 

 ing from the beak obliquely backward to the postero-basal ex- 

 tremity, is a rounded umbonal prominence, but the most promi- 

 nent portion of the valve is usually in front of this line near the 

 center of the shell ; the posterior slope from the umbonal promi- 

 nence is rather abrupt, nearly flat or slightly concave, the valves 

 becoming somewhat compressed towards the cardinal extremity; 

 in front the surface curves gently upward to the center of the 

 valve, then downward, becoming a little more abrupt as it ap- 

 proaches the anterior margin. Muscular impressions inconspicu- 

 ous. Lateral teeth of the hinge strong, nearly horizontal in 

 position, the anterior one sloping downward a little more than 

 the posterior; cardinal teeth not clear in the specimens. Free 

 margins of the valves crenate. Surface of the shell marked by 

 about 30 squarish, flat-topped, radiating costse, about as wide 

 or a little wider than the interspaces. In the condition in which 

 the type specimens are preserved, these costas are impressed upon 

 the surface of the casts from the margins to the beaks, but are 

 rounder on top than on the outside of the shell. 



Remarks. — At its typical locality in the top of the Wenonah 

 sand near Marlboro, this species occurs in great abundance. The 



