330 
The existence of a glacier in this valley is not imagined by the 
author to explain the origin of the detritus, as its having existed is 
proved by the polish on the rocks in situ, from the glacier of the Aar 
to Meiringen, a distance of twenty English miles, at the height of 
8000, 7000, and 6000 feet successively above the level of the sea; 
and even on the shores of the Lake of Thun. Similar phenomena 
have been noticed by M. Agassiz in Scotland, in the valleys of 
Loch Awe and Loch Leven, near Ballachalish, and in England in the 
neighbourhood of Kendal. 
The author then proceeds to describe the moraines of Switzerland, 
or the accumulations of blocks and pebbles deposited longitudinally 
on the borders, and transversely in front, of glaciers, and success- 
ively abandoned by them in their retreat. The longitudinal mo- 
raines differ from glacier-detritus remodelled or spread out by water, 
in being disposed in ridges with a double talus, one flank of which is 
presented to the glacier, and the other to the side of the valley ; and 
their continuity and parallelism at the same height easily distinguish 
them from the debris disposed along the bottoms of valleys by cur- 
rents. ‘l‘hey occur on the flanks of all glaciers, but they have been 
also observed by M. Agassiz where no glaciers exist, as in the val- 
leys of the Rhone, the Arve, the Aar, &c. ; likewise in Scotland, near 
Inverary, at Muc Airn, at the outlet of Look Traig, at Strankaer, 
and on the borders of the bay of Beauley; in Ireland to the south- 
east of Dublin, and near Enniskillen; and in England in the valley 
of Kendal, as well as near Penrith and Shap: 
The common origin of moraines, and of accumulations of rounded 
pebbles and of blocks, M. Agassiz says, cannot be doubted. The 
_ former are simple ridges formed on glaciers; the latter, materials 
rounded and polished under glaciers, or great masses of ice, and ex- 
posed by the melting.of the ice, and re-disposed by the water thus 
produced. 
The author next describes the differences in the internal arrange- 
ment of the various accumulations. In the stratified deposits the 
materials are comparatively much smaller than in glacier-detritus ; 
the pebbles also are elongated, and fine gravel and mud ordinarily 
form the upper beds. On the contrary, in the detritus of glaciers 
large and small materials are associated without order, the largest 
blocks being often in the upper part; and where very large angular 
blocks occur, they rest on the surface. In moraines there is a further 
distinction, blocks of all dimensions and every form are intermingled ; 
and this difference, he says, is easily understood, by recollecting that 
moraines are composed of the angular blocks which fall on the sur- 
face of the glacier, as well as of pebbles with rounded edges. 
The striated and polished surfaces, so often observed on solid 
rocks zz situ, are next described by M. Agassiz. Without denying 
absolutely the power of water to produce such effects, he says that 
he has sought for them in vain on the borders of rivers and lakes, 
and on sea- ciasies and that the effects produced by water are sinuous 
furrows proportioned to the hardness of the rocks; not even uniform 
polished surfaces, such as those presented by the rocks under dis- 
