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 

 (I20 1 ), near Matawan (ioo 4 , 101), Lenola (163); Navesink 

 marl, Atlantic Highlands (108), near Crawfords Corner (i26 7 ), 

 near Freehold (133), near Wain ford (i48 2 ), Crosswicks Creek 

 (149, I47 3 , I47 4 , 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 to the middle of the ventral margin, ventral 

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

 gin obtusely rounding 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 of the posterior mus- 

 cular ridge rather narrow and of 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 1 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. 



