U, S. GEOLOGICAL SURVEY 



BULLETIN 612 PLATE IV 



A, 



B. 



MARINE FOSSILS OF CRETACEOUS AGE. 

 A^ Oysters (Ostrea congesta); B^ Inoceramus lablatus 



Fr 



> . 



.- JrX'- 



C. CARBONIFEROUS FOREST. 



From vegetation of this sort the great deposits of coal were formed 



