EXPLANATION OF PLATE XLVII. 



EXOGYRA COSTATA Say, .............................................. p. 456 



i. View of a nearly perfect valve. 



Navesink marl; Crosswicks Creek, 



EXOGYRA PONDEROSA Roemer, ......................................... p. 458 



2. View of a nearly perfect valve. 



Marshalltov.'n clay-marl; near Swedesboro, (/7/). 



EXOGYRA sp., ........................................................ p. 460 



3. View of an internal cast of a lower valve. 



Mcrchantville clay-marl; Lenola, (/6j). 



OSTREA COXGESTA Con., ............................................. p. 435 



4. View of the internal cast of an attached valve. 



Cliff 'u'ood clay; Cliff-wood Point, (105). 



976 



