136 PALAEONTOLOGY OF NEW JERSEY. 



answer to include them longer under the same specific name. The other spe- 

 cies, having alternately one or two small ribs with closely set spines or ele- 

 vated granules between, and coarser ribs, with distant, strong spines, cannot 

 easily be mistaken when the surface, or matrix, is examined. The figure given 

 by Mr Gabb, cited above, is so poor that it cannot be satisfactorily deter- 

 mined which of these it was taken from. Both species are apparently 

 members of the group Trachycardium of Morch, 1852; while the present 

 one would fall under the genus Criocardium, proposed by T. A. Conrad in 

 1870, and the other one into Granocardimn, proposed by W. M. Gabb in the 

 Palseont. of California, Vol. II. Mr. F. Stoliczka, in the Palseont. Indica, rather 

 condemns both of these genera as being uncalled-for, with which idea I fully 

 concur. The features make perfectly good specific distinctions among the 

 ribbed forms of the Cardiidce, but to make generic distinctions of every slight 

 surface variation to which such shells are liable ought not to be tolerated. 

 Formation and locality. — The species has been recognized in the Lower 

 Green Marls at Holmdel, Monmouth, Freehold, and Burlington, New Jer- 

 sey; and Mr. Gabb's typical form seems to have been from Eufaula, Ala- 

 bama. It also occurs at Prairie Blufi", Alabama. The figured specimen is 

 in the collection ot the American Museum of Natural History. Others are 

 at Rutgers College. 



Genus PROTOGAEDIUM Beyrich. 



Cardium (Protocardium) perelongatum, n. sp. 



Plate XX, Figs. 20 and 21, and PI. XXI, Figs. 4 aud 5. 



Comp. Cardhtm Spillmani, Conrad. Jour. A. N. Sci., 2d series, Vol. Ill, p. 326, PI. 

 XXXIV, Fig. 3. Ibid., Vol. IV, p. 275 = Lcevicardinm Spillmani (Con.) 

 Meek, Geol. Surv. N. J., 1868, p. 727. 



Shell somewhat above a medium size, and very much elongated from 

 beak to base, even in internal casts; the diameter in this direction being one- 

 half greater than the antero-posterior diameter. Valves very ventricose, 

 with strongly inflated umbones and strong, elevated, moderately incurved 

 beaks, which are distinctly curved forward even in the cast. Hinge-line 

 short, highly arched. Posterior side of the shell short and abrupt; the 

 margin somewhat straightened. Anterior side rounded, but much shorter 



