MOLLUSCA. 393 



occur commonly in the Navesink marl, they are not usually asso- 

 ciated in the same locality, for where one of them is present in 

 abundance the other is usually rare or absent altogether. 



Formation and locality. — Merchantville clay-marl, Lorillard 

 (120I), near Matawan (Ioo^ loi), Lenola (163); Navesink 

 marl, Atlantic Highlands (108), near Crawfords Corner (126^), 

 near Freehold (133), near Walnford (148^), Crosswicks Creek 

 (i49> I47^ 147*, 195), near Jacobstown (150), near Mount 

 Laurel (166); Tinton beds, near Freehold (132). 



Geographic distribution. — New Jersey, Texas, Arkansas. 



Cucullaea woodburyensis n. sp. 

 Plate XXXIV., Fig. i. 



Description. — Shell large, the dimensions of the type specimen. 

 the internal cast of a left valve, being: length 75 mm., height 

 69 mm., convexity 28 mm., length of hinge-line 53 mm. An- 

 terior margin regularly rounding from the anterior extremity 

 of the hinge-line toi the middle of the ventral margin, ventral 

 margin less curved in its posterior half, the' postero-ventral mar- 

 gin obtusely rovmding into the subtruncate posterior margin 

 which is nearly vertical below and curves gently forward to the 

 posterior extremity of the hinge-line above. Beaks of moderate 

 size, those of the two' valves approaching somewhat closely. 

 Valves ventricose, without a sharp, umbonal ridge extending to 

 the postero-ventral extremity. Indentation O'f the posterior mus- 

 cular ridge rather narrow and oi moderate strength. 



Remarks. — -This species most closely resembles C. antrosa of 

 the Merchantville and Navesink faunas, but it is somewhat 

 shorter and more nearly erect in general aspect, besides having, 

 apparently, a much thinner shell, so that the internal cast is not 

 marked by the distinct marginal keel which is so characteristic 

 of that species. The species is a rare one in the Woodbury clay, 

 where a single specimen has been observed. 



formation and locality. — Woodbury clay, Lorillard (102). 



Geographic distribution. — New Jersey. 



