Apart from the fjords and lakes the chief beauties of the Alps are glaciers and waterfalls.
Among the great glaciers which stream from the peak the most noteworthy are those of Bossons and Taconnaz (northern slope) and of Brenva and Miage (southern slope).
A district of considerable extent in the centre of the island is occupied by snowfields, whence glaciers descend east and west to the sea.
Over the whole state there is a layer of drift deposited by the glaciers which once covered this region.
These trenches have for successive geological periods been the drainage valleys of immense lakes (probably also of glaciers) which formerly extended over the plateau or fiords of the seas which surrounded it.