'666 FOSSIL OSTREID^ OF NORTH AMERICA. 



PLATE L. 



ExoGYKA roNDEROSA Roeiuer. (Page 306.) 



Figs. 1, 2. — Upper aud iiudcr views of an example of about half full adult size. After 

 Roemer. 



OSTKEA TECTICOSTATA Gabb. (Page 301.) 



3. — A cluster of valves ; natural size. 

 4. — Interior view of a lower valve. 



OsTREA PELLUCIDA Meek & Hayden. (Page 296.) 



5. — Exterior view of a lower valve ; natural size. 

 6. — Opposite view of the same example. 



OsTREA MALLEiFORMis Gabb. (Page 297.) 



7. — Exterior view of an upper valve ; natural size. After Gabb. 



