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CHAPTER VIII. 

 THE Two ANTAGONIST DOCTRINES OF GEOLOGY. 



Sect. 1. Of the Doctrine of Geological Catastrophes. 



THAT great changes, of a kind and intensity 

 quite different from the common course of 

 events, and which may therefore properly be called 

 catastrophes, have taken place upon the earth's sur- 

 face, was an opinion which appeared to be forced 

 upon men by obvious facts. Rejecting, as a mere 

 play of fancy, the notions of the destruction of the 

 earth by cataclysms or conflagrations, of which we 

 have already spoken, we find that the first really 

 scientific examination of the materials of the earth, 

 that of the Sub-Apennine hills, led men to draw 

 this inference. Leonardo da Vinci, whom we have 

 already noticed for his early and strenuous assertion 

 of the real marine origin of fossil impressions of 

 shells, also maintained that the bottom of the sea 

 had become the top of the mountain ; yet his mode 

 of explaining this may perhaps be claimed by the 

 modern advocates of uniform causes, as more allied 

 to their opinion, than to the doctrine of catas- 

 trophes 1 . But Steno, in 1669, approached nearer 



1 " Here is a part of the earth which has become more light, 

 and which rises, while the opposite part approaches nearer to 



