ix.] PALAEONTOLOGY AND EVOLUTION. 213 



highly differentiated Sauropsidan fauna of the Trias in 

 Palaeozoic times ? The supposition that the Dinosaurian, 

 Crocodilian, Dicynodontian, and Plesiosaurian types 

 were suddenly created at the end of the Permian epoch 

 may be dismissed, without further consideration, as a 

 monstrous and unwarranted assumption. The supposi- 

 tion that all these types were rapidly differentiated out 

 of Lacertilia, in the time represented by the passage 

 from the Palaeozoic to the Mesozoic formation, appears 

 to me to be hardly more credible, to say nothing of the 

 indications of the existence of Dinosaurian forms in the 

 Permian rocks which have already been obtained. 



For my part, I entertain no sort of doubt that the 

 Eeptiles, Birds, and Mammals of the Trias are the 

 direct descendants of Eeptiles, Birds, and Mammals 

 which existed in the latter part of the 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. Terres- 

 trial 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 representation of the Permian 

 fauna ? 



It may be said that the Carboniferous formations 

 demonstrate the existence of a vast extent of dry 

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

 posed terrestrial Palaeozoic Vertebrate Fauna ought to 



