86 ORIGIN OF LIFE IN AMERICA 



Pleistocene times. Moreover, the Kamchatkan sheep (Ovis 

 jnivicola) is generally looked upon as a very near relation 

 to another Siberian wild sheep also inhabiting part of Kam- 

 chatka, and which has been found fossil by Tcherski in the 

 New Siberian Islands, viz., Ovis borealis. To judge by the 

 recent as well as by the fossil sheep in America, the genus 

 Ovis, to which all sheep belong, must, I think, have pene- 

 trated to North America, together with the mammoth and 

 other mammals, in comparatively recent geological times. 

 I shall return to the distribution of the American sheep 

 later on. 



I should have thought the genus to which the musk ox 

 (Ovibos) belongs was a better example of an American 

 intruder into Asia. Although no longer inhabiting the Old 

 World, its incursions into Asia and Europe must have taken 

 place about the same time as the mammoth's advent in 

 America. A still more striking instance of an American in- 

 vader into Asia is the camel, although Professor Osborn's * 

 statement, " in the Pleistocene the camels wandered into Asia 

 from America, while the bears passed them en route .tq 

 America," can scarcely be considered as strictly correct, 

 since two kinds of camels are known from the Pliocene 

 Siwalik deposits of India. The brilliant researches of 

 American palaeontologists have long ago acquainted us with 

 the fact that the camel family (Camelidae) inhabited America 

 since the dawn of the Tertiary Era, while the Indian occur- 

 rences alluded to are the earliest indications of camels having 

 reached the Old World. It is in Pliocene times, therefore, 

 or earlier even, that a land connection between America and 

 Asia must have existed, for no one would venture to propound 

 the theory that camels could have crossed from one continent 

 to another on an ice bridge. 



Sir Henry Howorthf collected in 1892 some valuable testi- 

 mony showing that the mammoth had lived in western Europe 

 in pre-Glacial times. In the following year Dr. Tcherski J 

 reminded us that a complete skeleton of the mammoth was 



* Osborn, H. F., " Faunal Relations of Europe and America," p. 58. 

 t Howorth, H. H., "The Maininoth and the Drift." 

 \ Tcherski, J. D., " Das Janaland," p. 47i. 



