J 22 PALAEONTOLOGY OF NEW JERSEY. 



Formation and localitij. — In the Lower Marl Beds at Bruere's pits, on 

 •Crosswicks Creek, near Walnford, and near Cream Ridge, New Jersey. 

 Mr. Conrad's types which are here figured were obtained from Arneytown, 

 New Jersey, and borrowed from the Academy of Natural Sciences of Phila- 

 delphia. 



Crassatella transversa. 

 Plate XVII, Figs. l(i ami 17. 



Crassatella transversa Gabb. P. A. N. Sci., Phil., 1861, p. 364. Synopsis, p. — . Meek, 



Check-list, p. — . Geol. Surv. N. J., 1868, p. 726. 

 Mea transversa (Gabb) Conrad. P. A. N. Sci., Phil., 1876, p. 275. 



Known from a single internal cast, representing a shell of moderate 

 size, with proportionally ventricose valves, which have a transversely 

 elongated form and rather prominent erect beaks, situated at about the 

 anterior third of the length, and are rather distant fi-oiu each other in the 

 cast. The anterior end is rather broadly rounded, and the posterior part 

 prolonged and narrow, with the extremity pointed below and curved down- 

 ward, leaving the basal line somewhat broadly .sinuate in the posterior third, 

 and very strongly convex opjiosite the beaks. The muscular scars have 

 been large and deep, being very strongly marked and prominent on tlie casts, 

 and the pallial line strong, with the border of the valve outside of the line 

 very much thickened and the margin strongly crenulate. 



The cast representing this species, that used by the author in the 

 original description, is very much more transverse than any other described 

 from New Jersey, except C. Delaivarensis of the same author. It is a larger 

 species, however, than that one, and of an entirely different form, being- 

 destitute of the angularit}- of the umbonal region, and more narrowed and 

 curved posteriorly with a rounded anterior end. In form it presents many 

 features in common with C. j)rotexta Conrad, from the Eocene sands at 

 Claiborne, Ala., but has been a much more ventricose and thicker shell, 

 with larger and more distant beaks, and more strongly marked muscular 

 scars. It would appear to have been a very rare species, as I have observed 

 onlv the one cast among all the collections which I have examined. 



