270 



TEE ICE AGE IN NORTE AMERICA. 



the unmistakable markings of which descend into it on the 

 upper side and emerge again at its lower margin.* 



There is so much general interest in the question as to 

 the formation of the Yosemite Valley that we append the 

 remarks of the same high authority concerning it : 



* " The Quaternary History of Mono Valley, California," pp. 281, 368, 869. 



