444 CRETACEOUS PALEONTOLOGY. 



Description. "Shell small, elongate, oval, ovate or irregularly 

 elliptical in outline, slightly curved, with a small, strongly-twisted 

 beak and moderately-sized ligamental area on the lower valve. 

 The lower valve usually shows a large cicatrized area of attach- 

 ment and is strongly plicated, the plica being usually sharply 

 rounded and very rugose from concentric lamellose lining. The 

 inner margins of the valves are also crenulated on the upper half 

 or two-thirds of their length, and more minutely so on the inner 

 border at the junction of the valves just below the ligamental 

 area. Muscular scar large, but only moderately marked. Upper 

 valves slightly convex and destitute of plications except near the 

 border." (Whitfield.) 



Remarks. This species was originally described from speci- 

 mens whose 'horizon is unknown, although they probably came 

 from some of the beds below the Navesink marl. The specimens 

 which have been so identified in the recent collections of the 

 Survey, are more or less imperfect casts from the Wenonah sand 

 near Marlboro. In general these Wenonah specimens somewhat 

 resemble the O. larva type of oysters, but the lower valve was 

 apparently attached uniformly by a much larger area than any 

 of the New Jersey forms here referred to 0. f ale at a, O. mesen- 

 t erica, and O. nasuta, and some of the specimens agree very well 

 with the type of the species except that they are modified casts 

 while the type has the shell itself preserved. 



Formation and locality. Wenonah sand, near Marlboro 



(130). 



Geographic distribution. New Jersey. 



Ostrea falcata Morton. 

 Plate XLIIL, Figs. 3-6. 



1830. Ostrea falcata Mort, Jour. Acad. Nat. Sci. Phil., ist ser., 



vol. 6, p. 50, pi. i, fig. 2. 

 1830. Ostrea falcata Mort., Am. Jour. Sci., ist ser., vol. 17, p. 



284; vol. 18, pi. 3, figs. 19-20. 

 1834. Ostrea falcata Mort., Synop. Org. Rem. Cret. Gr. U. S., 



p. 50, pi. 3, fig. 5. 



