"THE ORIGIN OF SPECIES." 321 



cal revolutions, wholesale creations and extinctions of 

 living beings, were the ordinary machinery of the geo- 

 logical epic brought into fashion by the misapplied 

 genius of Cuvier. It was gravely maintained and 

 taught that the end of every geological epoch was sig- 

 nalised by a cataclysm, by which every living being 

 on the globe was swept away, to be replaced by a brand- 

 new creation when the world returned to quiescence. 

 A scheme of nature which appeared to be modelled on 

 the likeness of a succession of rubbers of whist, at the 

 end of each of which the players upset the table and 

 called for a new pack, did not seern to shock anybody. 



I may be wrong, but I doubt if, at the present time, 

 there is a single responsible representative of these 

 opinions left. The progress of scientific geology has 

 elevated the fundamental principle of uniformitarian- 

 ism, that the explanation of the past is to be sought 

 in the study of the present, into the position of an 

 axiom ; and the wild speculations of the catastrophists, 

 to which we all listened with respect a quarter of a 

 century ago, would hardly find a single patient hearer 

 at the present day. No physical geologist now dreams 

 of seeking, outside the range of known natural causes, 

 for the explanation of anything that happened millions 

 of years ago, any more than he would be guilty of the 

 like absurdity in regard to current events. 



The effect of this change of opinion upon biological 

 speculation is obvious. For, if there have been no 

 periodical general physical catastrophes, what brought 



