16 TJw Mountaineer 



THE GLACIERS OF MOUNT RAINIER. 



Israel C. Russell. 



[Compiled by Alida J. Bigelow from Mr. Russell's re- 

 port in the 18th Annual Survey, Vol. 2, U. S. G. S.] 



The geology of Mount Rainier in its present gen- 

 eral form shows that when in its greatest perfection 

 it was a conical mountain, with gracefully concave 

 sides. The upper portion of the mountain is formed to 

 a large extent of fragments thrown out during ex- 

 plosive eruptions. Lava flows are also abundant, but 

 did not greatly modify the character of the slope as 

 determined by the falling of projectiles shot out of 

 the summit crater. 



The height of the mountain, between 15,000 and 

 16,000 feet, before the explosion that truncated its 

 summit, insured the gathering of perennial snows and 

 the formation of neve* fields and glaciers on its more 

 elevated portions. The main topographic changes that 

 have resulted must therefore be due to glacial action 

 and the eroding power of streams fed by the ice. 



Assuming that the peak was originally a perfectly 

 symmetrical cone with smooth, even sides, and that the 

 neve formed a uniform covering over the upper third 

 of its surface, the downward flow of the neve would 

 be equal. Many disturbing conditions come in, however, 

 in the case of a peak like Mount Rainier, composed 

 of loose agglomerate and lava sheets. Irregularities 

 in the surface of the cone, erosion by streams flow- 

 ing from the ice, unequal drifting of the snow, as well 

 as unequal melting, owing to variations in exposure 



* Neve is the granular snow-ice, before the formation into solid 

 glacial ice. 



