10 THE TRANSFORMATIONS OF THE ANIMAL WORLD 



mental idea, the merit of which we are too often apt 

 to forget is due to Cuvier, in view of the ex- 

 cessively severe and often unjust judgments which 

 the partizans of transformism have passed and still 

 pass on " Cuverian ideas " in matters of philosophical 

 palaeontology. - 



But what was, according to Cuvier, the mechanism 

 of these renewals of fauna which he so happily 

 brought to light ? The illustrious naturalist sets 

 forth his ideas with his customary clearness in the 

 admirable Discows sur les Revolutions du Globe, 

 which forms the introduction to his great work on 

 fossil bones. In his opinion the extinctions of 

 faunas have been at once complete and sudden, and 

 were provoked by violent geological events or 

 revolutions of the globe, largely, but not absolutely, 

 general in character. In favour of this hypothesis, 

 Cuvier adduces numerous facts of a geological order, 

 which, taken separately, and having regard to 

 the documents known at that epoch, are rigorously 

 exact. It is only their relations to each other 

 which have become disputable or even inexact. 



The existence of these revolutions of the globe 

 is attested by precise observations, some of which 

 have but a moderate value, such as the preservation 

 in the ice fields of Siberia of the corpses of great 

 quadrupeds, frozen with their skins, their hair, and 

 their flesh intact ; or, again, the position of fragments 

 of rocks and stones which have slipped down between 

 the solid strata of the earth's crust. 



But, to make up for this, other series of facts 

 reveal in the author most remarkable powers of 

 observation and geological sagacity we allude to 



