108 THE ICE AGE IN NORTH AMERICA. 



the range, where for a distance of 120 miles the average 

 height is 12,000 feet, while several individual peaks rise 

 higher than 16,000 feet. The snow-line in this range is from 

 11,000 to 12,000 feet above the sea-level, and in no ease do 

 the glaciers descend much lower than the 6,000-foot level. 

 The Ural Mountains — owing probably to their being so nar- 

 row as not to afford space for large snow-fields — are entirely 

 without glaciers. In Central Asia, however, where peaks in 

 many cases rise upwards of 20,000 feet, glaciers appear on a 

 grand scale in the Hindu Kush, the Tian Shan and the Altai 

 mountains and in those surrounding the Pamir. While 

 in the Himalayan range, about the head of the Indus, glaciers 

 of great size are reported. That at the head of the Basha 

 River "is over thirty miles in length, its lower part, for a 

 distance of twenty or twenty-five miles, being about a 

 mile and a half in width; above this — for some distance 

 at least — it is still wider, a marked feature being its small 

 inclination; along a large portion of its course it has an angle 

 of slope of not over one and a half or two degrees. 



" At the head of the Braldu Valley, an easterly tributary 

 of the Shigar, is one of the largest known glaciers — that of 

 Baltoro. This is said by the officers of the survey to be 

 thirty-five miles in length, ' measured along a central line from 

 its termination up to peak K 6 .' The Biafo Glacier, the foot 

 of which is about ten miles west of the Baltoro, is said to be 

 over forty miles long." * 



At the heads of the Sutlej and the Ganges similar glacial 

 developments are witnessed, as well as at various other points 

 throughout the whole length of the range. 



Passing to South America, we find, according to the best 

 reports, that until reaching the southern border of Chili gla- 

 ciers are infrequent and relatively small. According to Mr. 

 Whymper, no glaciers in Equador descend as low as 12,000 

 feet above the sea, and the glaciers in that region are largest 

 on the eastern side. Only on Cotopaxi, Chimborazo, and Illin- 



* Whitney's " Climatic Changes," pp. 284, 285. 



