28 WALKS AND TALKS. 



sembles that of a sea which has become suddenly frozen not 

 during a tempest, but at the instant when the wind has sub- 

 sided, and the waves, although very high, have become 

 blunted and rounded. These great waves are nearly parallel 

 to the length of the glacier, and intersected by transverse 

 crevasses, the interior of which appears blue, while the ice 

 is white on its external surface." Farther down, in the nar- 

 rower Glacier des Bois, the seracs and needles bristle over the 

 surface in mighty uplifts and fearful confusion. 



The crevasses really run iii any direction, according to the 

 nature of the underlying surface. In length they vary from 

 twenty feet to a mile. The downward direction is originally 

 vertical, but as the surface of the glacier moves more rapidly 

 than the deeper portions, the transverse crevasse assumes, 

 after a while, an inclination which gives it a dip up the val- 

 ley. Its depth may be ten or a hundred, or two hundred 

 feet ; and its width, which is a few inches at first, may grow 

 to fathoms. Forbes measured a crevasse at the base of the 

 Glacier du Geant, which had a breadth of not less than 1,214 

 feet. The two walls generally approach each other downward, 

 and we may sometimes safely descend to the bottom. The 

 wall-ice is absolutely immaculate, with a greenish blue trans- 

 parency. Down in the crevasse we hear the rills coursing 

 through the substance of the glacier, and sometimes the cen- 

 tral torrent rumbling along the bottom. The surface of the 

 glacier is white and granular, from the action of the sun. 

 Pools of water rest here and there pure, cool, and refreshing 

 and numerous rills flow over the surface, discharging them- 

 selves through crevasses and perforations in the ice-mass, into 

 some subglacial stream. 



Each of these great glaciers is bordered by a moraine, or 

 long ridge of material thrown off the surface in the course 

 of ages, and pushed up by the movements of the ice. It con- 

 sists of clay and rounded bowlders. It is completely unstrati- 

 fied, and resembles precisely, the till at the bottom of the 

 Drift. Tln-c lateral moraines at the present epoch, tower fifty 

 to eighty feet above their glaciers. The ice, for centuries, has 



