CHRONOLOGICAL SUCCESSION. 



43 



IDEAL SECTION OF THE CRUST OF THE EARTH. 



Fig. 17. 



Post-lertiary and Recent. 

 Pliocene. 



Cretaceous. 



Oolitic or Jurassic. 

 U Triassic. 



iferous. 



Devonian or Old Red Sandstone. 



Cambrian. 

 Huronian. 



Laurentian. 



