408 FOSSIL OSTEEID^. OF NOKTH A3IERICA. 



PLATE LXXI. 



OsTREA BouRGEOisii (Reraonil) Gabb. (Page 314.) 



Fig. 1. — Exterior view of a lower valve. After Gabb. 



OsTliEA VE8PERTINA Conrad. (Page 315.) 



Figs. 2, 3. — Exterior and interior views of a lower valve. 



4. — Exterior view of an upiier valve. After Conrad. 



