Erratics of the A lps. 297 



declivity i, consisting of ice, was nearly vertical, 

 as in the annexed section ; while the part between 

 d and b (Fig. 9) on the north side was entire- 

 ly covered with blocks, and inclined probably at 

 an angle of 30° or 35°. Owing to the mobility 

 of the blocks affording very insecure footing, we 

 ascended by the side of the fixed rock and partly 

 upon it, and walked about a mile along the surface in the direction 

 d e. Its appearance was new and strange, quite unlike anything I 

 had previously seen on glaciers. No ice was visible, no groups of 

 picturesque cones like spires, none of the huge transverse rents 

 called crevasses ; from side to side the surface was a sheet of frag- 

 ments great and small — resembling a dry river channel covered with 

 stones, and confined by walls of rock above 1000 feet in height. Yet 

 the coating of stones, though massive in appearance, was really thin ; 

 for, on shoving aside two or three of the smaller fragments, the ice 

 generally came into view, and no doubt constituted the entire mass 

 from e to /. The debris spread over the surface in this way, forming 

 what Charpentier terms the " superficial moraine," are all carried 

 ultimately, by the slow progressive movement of the glacier, to its 

 lower end, where they drop over the declivity, and, resting at its 

 foot, are called the " terminal moraine" (6). The fusion at the 

 lower end prevents this progressive motion from adding to the glacier's 

 length. 



I 1 Lit" ' *t" '■■". .'■ 



The glacier, by means of the mud, sand, and gravel which lie 

 below it, or adhere to its under part, polishes, scratches, and grooves 

 the rock in contact with its sides and bottom. The scratches and 

 grooves correspond with the line of the glacier's motion — that is, 

 they are horizontal, or nearly so, even upon vertical surfaces, and 

 their aspect, form, and direction, with the polishing which accom- 

 panies them, are- so peculiar and characteristic, that, when they are 

 found in any valley now never visited by permanent ice or snow, 

 they afford decisive evidence of the former existence of glaciers at 

 the place ; for they are such as no other agent known in nature 

 produces in such localities. The limestone of the Alps, at least that 

 of the valley of Hash, wastes too rapidly to retain the scratches and 

 grooves, unless where it is well covered with soil, but they present 

 themselves in abundance as soon as we enter the region of granite 

 and gneiss. Now, these characteristic marks of glacier action are 

 met with, not only in the neighbourhood of the present glacier, and 

 on the same level with it, but ten miles lower down in the valley, and 

 more than 1000 feet above it in vertical height. Agassiz describes 

 the grooves in the valley of Ober-Hasli as from an inch to a foot in 

 breadth. There are many of them, however, two feet in breadth, 

 some even three or four, and this on surfaces of rock almost vertical, 

 and 1500 feet above the traveller's head. They exist in thousands, 

 and are so conspicuous that, in wet weather, their glittering aspect 



