XI PALEONTOLOGY AND EVOLUTION 383 



Palaeozoic epoch, but not in any area of the present 

 dry land which has yet been explored by the 

 geologist. 



This may seem a bold assumption, but it will 

 not appear unwarrantable to those who reflect 

 upon the very small extent of the earth's surface 

 which has hitherto exhibited the remains of the 

 great Mammalian fauna of the Eocene times. In this 

 respect, the Permian land Vertebrate fauna appears 

 to me to be related to the Triassic much as the 

 Eocene is to the Miocene. Terrestrial reptiles 

 have been found in Permian rocks only in three 

 localities ; in some spots of France, and recently 

 of England, and over a more extensive area in 

 Germany. Who can suppose that the few fossils 

 yet found in these regions give any sufficient re- 

 presentation of the Permian fauna ? 



It may be said that the Carboniferous forma- 

 tions demonstrate the existence of a vast extent 

 of dry land in the present dry-land area, and that 

 the supposed -terrestrial Palaeozoic Vertebrate 

 Fauna ought to have left its remains in the Coal- 

 measures, especially as there is now reason to 

 believe that much of the coal was formed by the 

 accumulation of spores and sporangia on dry land. 

 But if we consider the matter more closely, I 

 think that this apparent objection loses its force. 

 It is clear that, during the Carboniferous epoch, 

 the vast area of land which is now covered by 

 Coal-measures must have been undergoing a 

 gradual depression. The dry land thus depressed 



