200 PALEONTOLOGY OF NEW JERSEY. 



small and indistinct, and the posterior one defined by a faintly impressed 

 line on the lower side, indicating a rather low ridge on the inside of the 

 shell. Pallial line well marked. Hinge features unknown. The median 

 portion on a cast used indicates the existence of several small teeth on this 

 portion. Exterior features unknown. 



This is a small and but sliglitly convex species, and is distinguished by 

 these features from any other of the genus, and also by the very small 

 space between the fillings of the beaks as well as by their small size and 

 slight prominence. The faintly marked muscular imprints might indicate a 

 young shell, but the other features are not what would exist on small speci- 

 mens of any of the other species known. 



Formation and locality. —In the Middle Marl Beds, at Mr. J. S. Cook's 

 pits, Tinton Falls, Monmouth County, New Jersey. 



ISOCARDIID^. 



Geuus ISOCARDIA Lamarck. 



Isocardia Conradi. 



Plate XXVI, Figs. 3 and 4. 



Isocardia Conradi Gabb. J. N. A. Sci., Vol. IV, p. 392, PI. LXVIII, Figs. 21 and 21 «. 

 Glossus Conradi Gabb. Synopsis, p. 162. Meek, Check-list, p. 12. 

 Bucardia Conradi (Gabb) Meek. Geol. Surv. N. J., 1808, p. 726. 



Mr. Gabb describes this shell as follows : "Triangular, equi valve ; beaks 

 large, inclined anteriorly; umbones large; anterior margin nearly straight, 

 basal sinuate, posterior subangular below, nearly straight above; surface 

 marked by fine concentric lines." The localities he gives as " Prairie Bluff", 

 Ala., and Timber Creek, N. J." 



The only specimen which I have seen of this species is that figured 

 as stated above. The specimen is a cast of the interior, and agrees Avell 

 with the above description. It corresponds quite closely in form Avith 

 I. Washita, Marcou (Geol. North America, p. 37, PI. Ill, Fig. 2), but is more 

 pointed at the anterior extremity and more angular on the umbonal ridge. 

 The specimen from which Mr. Gabb's figures and description are taken is 

 in the cabinet of the Academy of Natural Sciences of Philadelphia, and 

 although labeled as coming from Alabama, I believe to be the one he cites 



