238 DYNAMICAL GEOLOGY. 



small glaciers — the Grindelwald. and some others. The reason for the 

 difference in length between the glaciers on the Rhone valley slopes and on 

 the slopes outside is therefore chiefly topographical, though temperature 

 shortens the small streams on the Italian side. 



3. Glacier Cascades. — The Rhone glacier, east of the river Aar, at the 

 source of the Rhone, is a glacier-cataract (Figs. 207, 208, p. 235), and the 

 Glacier du Geant, of the Mont Blanc region, is another. The descent of 

 the latter is 140 feet ; it passes from the plateau of the Col du Geant over a 

 vertical rock-wall of the Tacul. 



4. Glacier Lakes. — Against the east side of the Aletsch Glacier lies Lake 

 Merjelen, a glacier-lake. Glacier-ice constitutes the western side or con- 

 fining barrier of the basin, — which is there 150 feet deep, — and a moraine 

 its bottom. Shiftings in the Aletsch Glacier empty the lake once in one to 

 four or five years, deluging part of the Rhone valley. 



The most accessible of the large glaciers of western North America is 

 the grand Muir Glacier, described first by Professor Muir of California 

 (1879), and later by Professor G. F. Wright (1886) and others. It descends 

 to Glacier Bay, at the head of Cross Sound, in latitude 58° 50', and has a 

 width at the sea level on Muir Inlet of about 5000 feet. Several streams 

 are here united over a circ of 30 to 40 miles, the two principal coming 

 from the northwest and north. In this direction is Mount Fairweather, 

 15,500 feet high, while Mount Crillon is to the south of west, 15,900 feet high. 



The glacier had a front on the water in 1886 (Wright) 250 to 408 feet in 

 height; but in 1890, of 250 feet as the maximum, there being evidence, 

 according to H. P. Cushing, of some retreat as well as diminished height 

 since 1886, the retreat on one side amounting to 3000 feet (1891). On either 

 side of Muir Inlet are mountains under verdure; those on the west reach a 

 height of 2900 feet, while on the east stands Mount Wright, 3150 to 5000 

 feet. Over the latter are " large areas of flowers in full bloom," " blue-bells, 

 daisies, buttercups, violets, the purple epilobium " ; and, " on the north side 

 of a slight elevation, great masses of snow were preserved in the very midst 

 of these brilliant flower-gardens." (Wright's Ice Age.) 



Other grand west- American glaciers are those of Mount St. Elias — an ele- 

 vation over 18,000 feet high. The general features of the great Malaspina 

 Glacier are shown on the accompanying map, from a paper by I. C. Russell. 

 The glacier is named after Malaspina, who explored the coast in 1792. It is 

 a great ice-plateau about 1500 square miles in area, and mostly 1500 feet 

 above the sea level. The Seward Glacier, one of its feeders, is 50 miles long 

 according to Russell, and the Agassiz and Guyot glaciers were given the 

 same length by Schwatka (1886). From the point between the Seward and 

 Agassiz glaciers, a high and broad medial moraine crosses the Malaspina 

 Glacier to the moraine of the border — a large and in part forest-covered 

 region of stones and earth. On the border of the Malaspina Glacier are 

 many lakelets, like Merjelen, which crevasses occasionally discharge; and 

 beneath it are drainage streams. (Russell, 1892.) 



