geologist Studer, quoted below, is undoubtedly true.[1] Not merely can the operations of extinct glaciers be traced in detail by means of the bosses of rock popularly termed roches moutonnées, but their effects in the aggregate, on a range of mountains or an entire country, can be recognised sometimes at a distance of fifteen or twenty miles from the incessant repetition of these convex forms.
It will not be uninteresting to consider, for a few moments, the way in which they are produced by glaciers; but first of all we must look back to the time when they had no existence.
§ 1. If ever the surface of the earth was as true as if it had been turned out from a lathe, it was certainly not so when the great glaciers—whose poor remnants we now see in the Alps—began to stretch far away from the mountains on to the lowlands of Switzerland and on to the plain of Piedmont,—unless geology is a lie. If geological reasoning is not a delusion and a snare, age upon age had passed away before this took place; rocks had crumbled into dust, and their particles had been re-arranged; lightning had struck the peaks; frost had cleft their ridges; avalanches had swept their slopes; earthquakes had fissured the soil; and torrents had transported the débris far and wide,—had eaten into the clefts, had scored the slopes, and had deepened the fissures for an indefinite length of time. It was, therefore, not a bran new world upon which the glaciers commenced to work—a globe which had been, as it were, just turned out of a mould; but it was scarred and weather-beaten; there were upon it hills and dales innumerable, cracks and chasms, asperities and depressions, which heat and cold had penetrated, and water had still further deepened. The world was incalculably old when this modern glacial period began its operations; and, although it continued for a long time, the glaciers
- ↑ "Un des faits les mieux constatés est que l'érosion des glaciers se distingue de celle des eaux en ce que la premiere produit des roches convexes ou moutonnées, tandis que la seconde donne lieu a des concavites."—Prof. B. Studer, Origine des Lacs Suisses.
