159 



such formations, would involve a lapse of time far 

 beyond the commonly-received chronology ; and that 

 this inference of high antiquity is greatly corro- 

 borated by the discovery of extinct animals in these 

 deposits — animals fitted for colder climates than that 

 of Europe, thus implying extensive oscillations in the 

 distribution of sea and land (and consequently vast 

 periods) by which these climatic changes were effected. 

 And further, that, high as the antiquity of man may 

 be in Western Europe, it does not fix the limit of his 

 age in Northern Africa or Asia, from whence all 

 history and tradition trace the descent of European 

 peoples ; nor does it arrest the inference that the 

 men of Asia, ancient as they may have been, were 

 descended from still earlier and more primitive races. 

 3. That, reviewing the whole animal scheme, and 

 seeing how thoroughly, both in the living and in 

 the extinct, it is pervaded by unity of plan, we are 

 constrained to apply to man the same methods of 

 research we apply to other animals, and to extend to 

 him whatever hypothesis may be advanced to ac- 

 count for the origin of the others. Applying these 

 methods, and knowing from physiology there is a 

 principle of variation at work among existing animals, 

 and learning from palaeontology that under a similar 

 principle of variation there has been a gradual ascent 

 in time from lower to higher life-forms, we are natur- 



