348 FOSSIL OSTREIDiE OF KORTH AMERICA. 



PLATE XLI. 



OsTREA DiLUViANA LinncBus. (Page 295.) 



Figs. 1,2.- -Exterior and interior views of the upper valve; naturalsize. Foralateral 

 view of the same example see Plate XL. 



OsTERA LUGUBRis Courad. (Page 297.) 



3. — Exterior view of an under valve ; natural size. 



