Masterpieces of Science 



period of time which is represented by the latter 

 half of the Tertiary deposits, seemed to me to be 

 the only explanation of the facts for which there 

 was even a shadow of probability. 



And, hence, I have ever since held that these 

 facts afford evidence of the occurrence of evolu- 

 tion, which, in the sense already denned, may be 

 termed demonstrative. 



All who have occupied themselves with the 

 structure of -4 nchitherium, from Cuvier onwards, 

 have acknowledged its many points of likeness to 

 a well-known genus of extinct Eocene mammals, 

 Palceotherium. Indeed, as we have seen, Cuvier 

 regarded his remains of Anchithcrium as those 

 of a species of Palceotherium. Hence, in attempt- 

 ing to trace the pedigree of the horse beyond the 

 Miocene epoch and the Anchitheroid form, I 

 naturally sought among the various species of 

 Palasotheroid animals for its nearest ally, and I 

 was led to the conclusion that the Palceotherium 

 minus (Plagiolophus) represented the next step 

 more nearly than any form then known. 



I think that this opinion was fully justifiable; 

 but the progress of investigation has thrown an 

 unexpected light on the question, and has brought 

 us much nearer than could have been anticipated 

 to a knowledge of the true series of the progen- 

 itors of the horse. 



You are all aware that, when your country was 



first discovered by Europeans, there were no 



traces of the existence of the horse on any part of 



the American Continent. The accounts of the 



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