116 PALEONTOLOGY OF ISTEW JERSICY. 



and later forms of the genus, founding this opinion of an apparent diflfer- 

 ence in the size of the pit behind the cardinal tooth of the right valve, and 

 the existence of a small pit behind the posterior cardinal tooth of the left 

 valve of these older forms, which does not exist in the more recent ones ; 

 and also on the fact that the inner margins of these older ones are always 

 crenulate, while mod of the Miocene and recent forms are smooth. I do not, 

 however, think these differences are of generic importance, and have not, 

 therefore, adopted the division either in a generic or subgeneric sense. In 

 the Appendix, pp. 5 and 6 of Kerr's Geological Report Qf North Car- 

 olina, Mr. Conrad describes the genus Etea, also a division of CrassatcJJa, 

 and in the Proceedings of the Academy of Natural Sciences, 1876, p. 275, 

 refers to it the following species : Crassatella Monmouthetms, C. trai/sversa, 

 C. Delawarensis Gabb, and C. prora Conrad. I have not thought it worth 

 while to retain this division any more than the above. 



Crassatella vadosa. 

 Plate XVII, Figs. 12-15. 



Crassatella vadosa Mortou! Syuopsis, p. 66, PI. XIII, Fig. 12. Gabb, Syu. Cret. Form., 

 p. 113. P. A. N. Sci., 1876, p. 310. Meek, Check-list Suiitb. lust., p. IL 

 Geol. Kept. N. J., 1863, p. 726. Stobczka, Pal. Indica, p. 295. 



C. lintea aud P. Repleyana (Con.) Gabb. P. A. N. S., Pbii., 1876. p. 310. 



Coinp. Crassatella lintea Con. J. A. N. Sci., new ser., Vol. IV, p. 279, PI. XL VI, Fij;. 5. 



Comp. Crassatella CaroUnensis Conrad. Kerr's X. Car. Kept., p. C, Appendix. 



This shell as usually identified in New Jersey is seen under two con- 

 ditions of preservation, one as single valves preserved on the soft marl, 

 the other as internal casts of both valves. The former is transversel}- 

 broad-ovate, or very obscurely subtriangular, the valves rather moderately 

 convex with a somewhat obscure umbonal ridge extending from the beak 

 to the postero-basal angle. The shell is very high opposite the Ijeaks, and 

 rapidly narrows toward the posterior extremity to less than half the height 

 at the former place. The anterior end is nearl}- one-third or more than 

 one-third of the length of the entire shell, and is rounded, with the longest 

 point below the middle of the height. Above this point the margin slopes 

 rather rapidly and with but little curvature to the beaks. Beaks prominent 

 and pointed. Posterior margin obliquely truncated, and the basal margin 

 fullest and most sharply curved nearly opposite the beaks. The surface of 



