IDEAL SECTION OF THE CRUST OF THE EARTH. I 3 



IDEAL SECTION OF THE CRUST OF THE EARTH. 



Fig. 2. 



f *~~~~- ^""" - x 



/(' 



}> Post-tertiary and Recent. 

 | Pliocene. 



Miocene. 

 Eocene. 



Cretaceous. 



Oolitic or Jurassic. 



Triassic. 

 Permian. 



Carboniferous. 



Devonian or Old Red Sandstone. 



Silurian. 



Cambrian. 

 Huronian. 



Laurentian. 





