MOUNT RAINIER 



into two short lobes on a rounded boss in the middle 

 of the channel. This boss, but a short time ago, was 

 overridden by the glacier and then undoubtedly gave 

 rise to an ice dome of the kind so numerous farther 

 up on the North Mowich Glacier and also character- 

 istic of the Winthrop Glacier. 



Separated from the ice fields of the North Mowich 

 Glacier by a great triangular ice field (named Ed- 

 munds Glacier) lies the South Mowich Glacier, also a 

 cirque-born ice stream, heading against the base of 

 the Liberty Cap massif. It is the shortest of the 

 western glaciers, measuring only a scant 3 miles. 

 Aside from the snows accumulating in its ill-shaped 

 cirque it receives strong reinforcements from its neigh- 

 bor to the south the Puyallup Glacier. 



Toward its lower end it splits into two unequal lobes, 

 the southernmost of which is by far the longer. Sharp 

 cut rock wedges beyond its front show that when the 

 glacier extended farther down it split again and again. 



The north lobe is of interest because the stream that 

 cascades from the Edmunds Glacier runs for a con- 

 siderable distance under it. In the near future the 

 lobe is likely to recede sufficiently to enable the torrent 

 to pass unhindered by its front. 



What especially distinguishes the Puyallup Glacier 

 from its neighbors to the north is the great elevation 

 of its cirque. The Carbon, North Mowich, and 

 South Mowich Glaciers all head at levels of about 

 10,000 feet. The amphitheater of the Puyallup Gla- 

 cier, on the contrary, opens a full 2,000 feet higher 

 up. Encircled by a great vertical wall that cuts into the 

 Liberty Cap platform from the south, it has evidently 

 developed through glacial sapping from a hollow of 

 volcanic origin. From this great reservoir the Puyal- 

 lup Glacier descends by a rather narrow chute. Then 

 it expands again to a width of three-fourths of a mile 

 and sends a portion of its volume to the South Mowich 

 Glacier. In spite of this loss it continues to expand, 



236 



