MOUNT RAINIER 



And thus, in some localities, one may behold the ap- 

 parently incongruous spectacle of large and heavy 

 rocks supported on snow pillars alongside of little 

 fragments that have sunk into the ice. 



There is also a limit to the depth which the little 

 wells may attain ; as they deepen, the rock fragment 

 at the bottom receives the sun heat each day for a 

 progressively shorter period, until at last it receives so 

 little that its rate of sinking becomes less than that of 

 the melting glacier surface. Nevertheless it will be 

 clear that the presence of scattered rock debris on a 

 glacier must greatly augment the rate of melting, as 

 it fairly honeycombs the ice and increases the number 

 of melting surfaces. Wherever the debris is dense, on 

 the other hand, and accumulates on the glacier in a 

 heavy layer, its effect becomes a protective one and 

 surface melting is retarded instead of accelerated. The 

 dirt-covered lower ends of the glaciers of Mount 

 Rainier are thus to be regarded as in a measure pre- 

 served by the debris that cloaks them ; their life is 

 greatly prolonged by the unsightly garment. 



In many ways the most interesting of all the ice 

 streams on Mount Rainier is the Carbon Glacier, the 

 great ice river on the north side, which flows between 

 those two charming natural gardens, Moraine Park 

 and Spray Park. The third glacier in point of length, 

 it heads, curiously, not on the summit, but in a pro- 

 found, walled-in amphitheater, inset low into the 

 mountain's flank. This amphitheater is what is tech- 

 nically known as a glacial cirque, a horseshoe-shaped 

 basin elaborated by the ice from a deep gash that 

 existed originally in the volcano's side. It has the 

 distinction of being the largest of all the ice-sculptured 

 cirques on Mount Rainier, and one of the grandest 

 in the world. It measures more than a mile and a 

 half in diameter, while its head wall towers a sheer 

 3,600 feet. So well proportioned is the great hollow, 

 however, and so simple are its outlines that the eye 



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