CHRONOLOGICAL SUCCESSION OF AQUEOUS ROCKS. 31 



V 



age of the Old Red Sandstone could possibly be deposited. 

 2. The Old Red Sandstone might have been deposited upon 

 the Silurian, and then the whole might have been elevated 

 above the sea, and subjected to an amount of denudation 

 sufficient to remove the Old Red Sandstone entirely. In 

 this case, when the land was again submerged, the Carbon- 

 iferous Rocks, or any younger formation, might be deposited 

 directly upon Silurian strata. From one or other of these 

 causes, then, or from subsequent disturbances and denuda- 

 tions, it happens that we can rarely find many of the primary 

 formations following one another consecutively and in their 

 regular order. 



In no case, however, do we ever find the Old Red Sand- 

 stone resting upon the Carboniferous, or the Silurian Rocks 

 reposing on the Old Red. We have therefore, by a compari- 

 son of many different areas, an established order of succession 

 of the stratified formations, as shown in the subjoined ideal 

 section of the crust of the earth (fig. 9). 



The main subdivisions of the Stratified Rocks are known 

 by the following names : 



1. Laurentian 



2. Cambrian (with Huronian ?). 



3. Silurian. 



4. Devonian or Old Red Sandstone. 



5. Carboniferous. 



6. Permian 1 AT ^ , , , 



^ . . > New Red Sandstone. 



7. Triassic ) 



8. Jurassic or Oolitic. 



9. Cretaceous. 



10. Eocene. 



11. Miocene. 



12. Pliocene. 



13. Post-tertiary. 



& M r r 



