340 FOSSIL OSTREIDiK OF NORTH AMKRICA. 



PLATE XXXVn. 

 OsTREA suBSPATULATA Forbes. (Page 301.) 



Fig. 1.— Lateral view of a separate valve ; natural size. 



2.— Interior view of the same example. After Forbes. 



OsTREA CORTEX Courad. (Pago 294. ■> 



3.— Exterior view of a separate valve; natural size. 

 4.— Similar view of another specimen. After Conrad. 



OsTREA PLUMOSA Morton. (Pago 299.) 



5.— Upper view of a specimen somewhat distorted by pressure ; natural size. 

 6.— Exterior view of the upper valve of another example. 



