FOSSILS. 



21 



1. Lower and Upper Silurian, Devonian, Carboniferous, and Permian; one great life period. 



Thickness of the rocks, over 50,000 feet. 



Plants, 



Radiated Animals, 

 Mollusca, or Shells, 

 Articulated Animals, 

 Vertebrate Animals, 



Plants, 



Radiata, 



Mollusca, 



Articulate, 



Vertebrata, 



Plants, 



Radiata, 



Mollusca, 



Articulata, 



Vertebrata, 



Plants, 



Radiata, 



Mollusca, 



Articulata, 



Vertebrata, 



Plants, 



Radiata, 



Mollusca, 



Articulata, 



Vertibrata, 



Plants, 



Radiata, 



Mollusca, 



Articulata, 



Fishes, 



Reptiles, 



Birds, 



Mammals, 



Lithichnozoa, 



Plants, 



Radiata, 



Mollusca, 



Articulata, 



Vertebrata, 



2. Triassic Formation. 



3. Oolitic, or Jurassic Formation. 



4. Cretaceous Formation. 



5. Tertiary Formation. 



6. Alluvial Formation. 



7. Living Species. 



1183 



768 



2708 



641 



328 



115 

 150 

 776 

 22 

 143 



355 

 626 

 2332 

 382 

 552 



122 



1581 



2817 



177 



241 



945 

 2081 

 7913 

 1828 

 1557 



31 

 12 



126 

 2 

 2 

 9 



55 



219 



20 



69403 



4818 



11482 



67360 

 18085 



2. Each rock formation is characterized by its peculiar group of fossils not found in 

 any other, so that a paleontologist on seeing a specimen can usually tell from what part 

 of the series it came. 



