660 



AMERICAN FORESTRY 



Photo by Geo. V. Ceasar. 



LOWER COURSE OF CARBON GLACIER. 

 THIS SHOWS THE MEDIAL MORAINES. IN THE BACKGROUND ARE THE MOTHER MOUNTAINS. 



process is particularly effective in the 

 great cleft at the glacier's head, be- 

 tween ice and cliff. This abyss is 

 periodically filled with fresh snows, 

 which freeze to the rock; then, as the 

 glacier moves away, it tears or plucks 

 out the frost-split fragments from the 

 wall. Thus the latter is continually 

 being undercut. The overhanging por- 

 tions fall down, as decomposition les- 

 sens their cohesion, and so the entire 

 cliff recedes. 



West of the profound canyon of the 

 Carbon River, there rises a craggy range 

 which the Indians have named the 

 Mother Mountains. From its narrow 

 backbone one looks down on either side 

 into broadly open, semicircular valley 

 heads. Some drain northward to the 

 Carbon River, some southward to the 

 Mowich River. Encircling them run 

 attenuated rock partitions, surmounted 

 by low, angular peaks; while cutting 

 across their stairwise descending floors 

 are precipitous steps of rock, a hundred 

 feet in height. On the treads lie 

 scattered shallow lakelets, strung to- 



gether by little silvery brooks trickling 

 in capricious courses. 



Most impressive is the basin that lies 

 immediately under the west end of the 

 range. Smoothly rounded like a bowl, 

 it holds in its center an almost circular 

 lake of vivid emerald hue that mysteri- 

 ous body of water known as Crater 

 Lake. Let it be said at once that this 

 appellation is an unfortunate misnomer. 

 The basin is not of volcanic origin. It 

 lies in lava and other volcanic rocks, to 

 be sure, but these are merely spreading 

 layers of the cone of Mount Rainier. Ice 

 is the agent responsible for the carving 

 of the hollow. It was once the cradle 

 of a glacier, and that ice mass, gnawing 

 headward and deploying even as the 

 Carbon Glacier does today, enlarged its 

 site into a horseshoe basin, a typical 

 glacial cirque. The lake in the center is 

 a strictly normal feature; many glacial 

 cirques possess such bowls, scooped out 

 by the eroding ice masses from the 

 weaker portions of the rock floor; only 

 it is seldom that such features acquire 

 the svmmetrv of form exhibited by 



