of the lioclcs forming the beds of Glaciers in the Alps. 565 



thod of working the ore in that mountain is fast destroying the 

 best mines ; that new trials have not been attended with anything 

 like success ; and that the hardness of the rock renders sinkings 

 very expensive, and compels adventurers with limited funds to aban- 

 don their undertakings, unless ore be speedily obtained. 



On the polished and striated surfaces of the rocks Mhicli form 

 the beds of Glaciers in the Alps, by Professor Agassiz. 



This paper was accompanied by a series of plates intended to re- 

 present the effect of glaciers upon the rocks over which they move. 



These effects, consisting of surfaces highly polished, and covered 

 with fine scratches, either in straight lines or curvilinear, according 

 to the direction of the movement of the glacier, are constantly found, 

 not only at the lower extremity, where thej' are exposed by the 

 melting of the glaciers, but also, wherever the subjacent rock is 

 examined, by descending through deep crevices in the ice. Grains 

 of quartz and other fragments of fallen rocks, which compose the 

 moraines that accompany the glaciers, have afforded the material 

 which, moved by the action of the ice, has produced the polish and 

 scratches on the sides and bottom of the Alpine valleys through which 

 the glaciers are continually, but slowly descending. It is impossible 

 to attribute these effects to causes anterior to the formation of the 

 glacier, as they are constantly present and parallel to the direction of 

 the movement of the ice. They cannot be considered as the effects 

 of an avalanche, for they are often at right angles to the direction in 

 which an avalanche would descend ; they are constantly sharp and 

 fresh beneath existing glaciers, but less distinct on surfaces which 

 have for some time been left exposed to atmospheric action by the 

 melting of the ice. In the valley of the Viesch, the direction of the 

 scratches is from north to south, or towards the Rhone; the direction of 

 those which accompany the glacier of the Rhone is from east to west ; 

 that of those beneath the glacier of the Aar is first from west to 

 east, as far as the Hospice of the Grimsel ; and then from south to 

 north, from the Grimsel to the Handeck. If we would account for 

 these scratches by the action of water, we must imagine currents of 

 enormous depth fiUing these highest Alpine valleys, and descending 

 in opposite directions from the narrow crest that lies between them. 

 In the upper part of the valley of the Viesch, is a glacier, beneath 

 which runs a raj)id torrent, co-extensive in length with the great 

 current, to which the above hypothesis would attribute the polish 

 and scratches on the rocks of the valley. This small torrent 

 corrodes the bottom of the valley into sinuous furrows and irregular 

 holes, and polishes the sides of its bed ; but the polish is of a different 

 aspect from that ])roduced by the action of the ice, and of the stones 

 and sand wliich it carries with it. 'i'he polished surfaces beneath 

 the ice are often salient and in high relief. The sides also of the 

 valleys adjacent to the actual glaciers arc frequently polished and 

 scratched at great heights above the ice, in a manner identical with 

 the surface beneath it, but different from the polish of the bed of 

 the torrent. 



