212 PALEONTOLOGY OF NEW JERSEY. 



Crassatella littoralis. 



Plate XXVIII, Figs, (i and 7. 



Crassatella littoralis Conrad. Am. Jour. Conch., Vol. V, p. 41, PI. I, Fig. 3. 



0. (Conrad). Meek, Geol. Surv. N. J. 1868, p. 731. 



C. pleuronema Conrad. On label with specimens in A. ZST. Sci. Philadelphia. 



Shell rather below a medium size, transversely oval or ovate, with 

 moderately convex valves and small inconspicuous beaks, which are near 

 the anterior end of the shell and are directed forward. Anterior end wider 

 than the opposite, the greatest width of the valves being across the shell at 

 the position of the beaks. Hinge-line long posteriorly, slightly curved; 

 posterior end narrowed and slightly truncate; basal line gently curved 

 throughout its entire length. Surface of the shell marked by moderately 

 fine, even, concentric ridges parallel to the margin, which are more abruptly 

 bent in crossing the position of the umbonal ridge, this latter feature being 

 very subdued. 



In the condition of internal casts, which is the most frequent, the form 

 is transversel)^ ovate, with more prominent beaks, situated considerably 

 within the anterior third of the length and directed forward, incurved and 

 approximate; a perceptible umbonal angle, or with the disk nearly evenly 

 convex; very inconspicuous muscular scars, and a moderately marked fur- 

 row along the line of the pallial attachment. The most perfect casts show 

 the margin of the valves tg have been iinel}' creuulated. 



I have not seen perfect shells, and only a few fragments preserving 

 their substance to any extent, the best one observed being that figured; there- 

 fore the hinge features are unknown to me. In form the casts are quite 

 distinct from any of the others recognized in the State and will not be 

 readiljr mistaken, the transverse oval form, with small incurved beaks, serv- 

 ing to distinguish it. Its nearest allied form is C. Conradi, with which it 

 is associated in the same beds. From that it may be distinguished by 

 its greater length, less angular umbonal ridge, less erect beaks, and nar- 

 rower and rounded posterior end. 



Formation and locality. — Mr. Conrad describes the species as from Shark 

 River, and places it under the head of ^^JEocenc species^ It, however, occurs, 



