PLATE VI. 



Fig. 1. Ostrea crenulimarginata Gabb. Exterior of left valve. (After Aldrich and Harris.) 



Page 



Alabama 36 



2. Ostrea crenulimarginata Gabb. Interior of left valve. (After Aldrich and Harris.) 



Alabama 36 



3. Ostrea crenulimarginata Gabb. Interior of unusually rounded form. (After Aldrich 



and Harris.) Alabama 36 



4. Ostrea crenulimarginata Gabb. Young shell, rounded variety. Height 25 mm. Sol- 



dado Rock. Midway Eocene 36 



5. Ostrea eynthia n. sp. Flat, upper valve resting on convex lower. Height 140 mm. 



Showing commencement of concentric deposits of silicon. Soldado Rock. Midway 

 Eocene 37 



6. Ostrea thalassoklusta n. sp. Height 23 mm. Soldado Rock. Midway Eocene 39 



7. Ostrea cf. percrassa Conrad and compressirostra Conrad. Shell completely disguised 



by concentric silicious deposits. Length 130, height 90 mm. Soldado Rock. Mid- 

 way Eocene 37 



