TWO ANTAGONIST DOCTRINES OF GEOLOGY. 661 



remains occurred, were entirely different, it 

 said, in two successive epochs : a new creation 

 appears to have intervened; and it was readily 

 believed that a transition, so entirely out of the 

 common course of the world, might be accompanied 

 by paroxysms of mechanical energy. Such views 

 prevail extensively among geologists up to the pre- 

 sent time : for instance, in the comprehensive theo- 

 retical generalizations of Elie de Beaumont and 

 others, respecting mountain-chains, it is supposed 

 that, at certain vast intervals, systems of moun- 

 tains, which may be recognized by the parallelism of 

 course of their inclined beds, have been disturbed 

 and elevated, lifting up with them the aqueous 

 strata which had been deposited among them in 

 the intervening periods of tranquillity, and which 

 are recognized and identified by means of their 

 organic remains : and according to the adherents of 

 this hypothesis, these sudden elevations of moun- 

 tain-chains have been followed, again and again, 

 by mighty waves, desolating whole regions of the 

 earth. 



The peculiar bearing of such opinions upon the 

 progress of physical geology will -be better under- 

 stood by attending to the doctrine of uniformity, 

 which is opposed to them, and with the considera- 

 tion of which we shall close our survey of this 

 science, the last branch of our present task. 



