^ummtte 



^fr^HE higher mountain-ranges rise far above 

 ^S the zone of life and have summits that are 

 deeply overladen with ancient snow and ice, but 

 the upper slopes and summits of the Rocky 

 Mountains of Colorado and the Sierra of Cali- 

 fornia are not barren and lifeless, even though 

 they stand far above the timber-line. There is 

 no other mountain-range on the earth that I 

 know of that can show such a varied and vigor- 

 ous array of life above the tree-line as do these 

 ranges. In the Alps the upper slopes and sum- 

 mits stand in eternal desolation, without life 

 even in summertime. The icy stratum that 

 overlies the summit Alps is centuries old, and is 

 perpetual down to nine thousand feet. Timber- 

 line there is only sixty-four hundred feet above 

 sea-level. How different the climatic conditions 

 in the Rocky Mountains and in the Sierra, where 



IOI 



