MANUAL OF ZOOLOGY. 



IDEAL SECTION OF THE CRUST OF THE EARTH. 



Fig. i. 



Post-Tertiary and Recent. 

 Pliocene. 



Miocene. 

 Eocene. 



Cretaceous. 



Oolitic or Jurassic. 

 L> Triassic. 



Permian. 



Carboniferous. 



Devonian or Old Red Sandstone. 



Silurian. 



Cambrian. 

 Huronian. 



Lauren tian. 



