MOLLUSCA. 577 



shells themselves have been removed by solution and the soft 

 material in which they were buried, has been compressed so it 

 is possible that the radiating costse of the outside of the shell 

 have been impressed- more strongly upon the surface of the casts 

 than they would be under other conditions. A large proportion 

 of the specimens in this locality have been more or less distorted, 

 but there is little difficulty in recognizing the species by reason of 

 its small size and its smooth costae which are always about 30 

 in number. In the undistorted specimens the subrhomboidal out- 

 line is always quite noticeable. 



This species occurs abundantly at Corsicana, Texas, with the 

 shell itself perfectly preserved. In the central portion of the in- 

 side of the shell in the Texas examples, there are radial rows of 

 rather large pits occupying the position of the interspaces between 

 the ribs on the outside. These pits pierce the inner layers of the 

 shell only, but when the outside is slightly exfoliated they' appear 

 as perforations through the shell. The surface is marked by 

 concentric, sublamellose lines of growth which are frequently 

 eroded. The species should be compared with C. choctawensis 

 Shum.,^ but that species possesses much more conspicuous con- 

 centric markings which give to the ribs a crenulated appearance. 



Formation and locality. — Wenonah sand, near Marlboro 

 (130) ; ? Red Bank sand, near Middletown (112). 



Geographic distribution. — New Jersey, Texas. 



Cardium eufaulensis Conrad. 

 Plate LXIIL, Figs. 17-20. 



i860. Cardium Hufaulensis Con., Jour. Acad. Nat. Sci. Phil., 



2d ser., vol. 4, p. 282, pi. 46, fig. 12. 

 1861. Cardium Bufalensis Gabb, Synop. Moll. Cret. Form., p. 



162 (106). 

 1864. Cardium eufalense Meek, Check List. Inv. Foss. N. A., 



Cret. and Jur., p. 12. 

 1868. Cardium (Trachycardium) Bufalense Con., Cook's Geol. 



N. J., p. 726. 



' Trans. St. Louis Acad. Sci., vol. i, p. 599 ; also White's Cont. to Pal., No. 2, 

 pi. 18, figs. 7a-c. 



37 PAI. 



