RELICS OF MAN IN THE GLACIAL PERIOD. 301 



inference being, not that man is so extremely ancient in 

 California, but that many of these plants and animals 

 have continued to a more recent date than has ordinarily 

 been supposed. 



The connection of these lava-flows on the Pacific coast 

 with the Glacial period is unquestionably close. For 

 some reason which we do not fully understand, the vast 

 accumulation of ice in North America during the Glacial 

 period is correlated with enormous eruptions of lava west 

 of the Rocky Mountains, and, in connection with these 

 events, there took place on the Pacific coast an almost 

 entire change in the plants and animals occupying the 

 region. Mr. Warren Upham is of the opinion that on 

 the Pacific coast they lingered much later than in the 

 region east of the Rocky Mountains. Indeed, it is pretty 

 certain that not many centuries have elapsed since the 

 glacial phenomena of the Sierra Nevada Mountains were 

 much more pronounced than they are at the present time, 

 and it is equally certain that there have been vast erup- 

 tions of lava in California within three hundred years. 



From these data, therefore, Mr. Becker has real foun- 

 dation for his suggestion that perhaps in the Glacial 

 period California was a kind of health resort for Pliocene 

 animals, as it is at the present time for man ; or, at any 

 rate, that the later date of the accumulations permitted 

 the animals to survive there much longer than in the re- 

 gion east of the Rocky Mountains. 



Further discussion of the preceding facts will profit- 

 ably be deferred until, in the next two chapters, the ques- 

 tions of the cause and date of the Glacial period have 

 been considered. 



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