588 HISTORY OF GEOLOGY. 



elevated the existing continents. This distinction was assented to bj 

 many succeeding geologists. The forces which have raised into the 

 clouds the vast chains of the Pyrenees, the Alps, the Andes, must have 

 been, it Avas deemed, something very different from any agencies now 

 operating. 



This opinion was further confirmed by the appearance of a complete 

 change in the forms of animal and vegetable life, in passing from one 

 formation to another. The species of which the remains occurred, 

 were entirely different, it was 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 present time : for instance, 

 in the comprehensive theoretical generalizations of Elie de Beaumont 

 and others, respecting mountain-chains, it is supposed that, at certain 

 vast intervals, systems of mountains, 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 eleva- 

 tions of mountain-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 understood by attending to the doctrine of uni- 

 formity, which is opposed to them, and with the consideration of 

 which we shall close our survey of this science, the last branch of our 

 present task. 



Sect. 2. Of the Doctrine of Geological Uniformit;/. 



THE opinion that the history of the earth had involved a series of 

 catastrophes, confirmed by the two great classes of facts, the symptoms 

 of mechanical violence on a very large scale, and of complete changes 

 in the livino- things by which the earth had been tenanted, took strong 



O O J 



hold of the geologists of England, France, and Germany. Button, 

 though he denied that there was evidence of a beginning of the pre- 

 sent state of things, and referred many processes in the formation of 

 strata to existing causes, did not assert that the elevatory forces which 

 raise continents from the bottom of the ocean, were of the same order 



