SECTIOISr VI. 



LAMELLIBRANCHIATA FEOM THE EOCENE MAELS OF NEW JEKSEY. 



OSTREID^. 



Genus OSTEEA Liuuaens. 



Ostrea glauconoides, n. sj). 

 Plate XXIX, Fig. 2. 



Shell small, obliquely ovate, lower valve rather shallow, narrow at the 

 apex on the body of the valve, but with a proportionally large wing on the 

 inner (anterior 1) side, which gives the cast a somewhat Avicula-like aspect. 

 Lower part of the valve abruptly curved to one side, which, if the larger 

 valve shall be called the right, would be anterior, the same as tbe alated 

 side of the hinge, and is somewhat prolonged at this point. Muscular im- 

 pression faintly marked, but broad, and near the middle of the valve. Sur- 

 face of the shell, as indicated on the cast, marked by rather strong, rounded, 

 radiating ribs. 



Only a single cast of a valve of this species has been noticed, but it 

 differs so greatly from any other one in these beds, or even in the New Jer- 

 sey formations, that it cannot be easily mistaken. It seems to have an ex- 

 tension of the hinge on each side of the beak, but this point cannot be very 

 Avell determined from the specimen under examination. There are several 

 small species of Ostrea in the Eocene which more or less resemble this one, 

 like 0. AlabamiensiS Lea, from Claiborne, but none of them are near enough 

 to be mistaken for it, and as this one is so marked and quite uncommon, it 

 is well that attention should be called to its existence in these layers. 

 This same species occurs in the white marly limestone at or near the 

 base of the Eocene beds at Claiborne, Ala, where it attains a size 



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