Extract

Since Agassis, forty-five years ago, pointed out striæ and surface shapings over various parts of Scotland as proof of an ice-sheet having once covered much of the country, my attention has been drawn to such evidence wherever it was my fortune to meet with it; and I have long held that ice and water, and not water alone, has had much to do in shaping the river valleys and forming those terraces which contain no marine remains, met with both on the east and west watersheds of Scotland; and that the Parallel Roads of Lochaber in place of being ‶merely contour lines etched on the sides of the valleys by long continued but slight agitation of the margin of the water which filled the glens to various depths in succession, as the barriers which dammed it up were at intervals broken down,″¹ are sea beaches, river terraces, or ancient roads, formed as the margins of the ice filled the glens when the last great glaciation was slowly passing away. Before entering on this discussion, it is well to bear in mind, that though ice is a solid rigid substance, it has many of the properties of a liquid, and from its viscidity fits itself to the valley. When the glaciation was greatest, ice covered much of Scotland, and filled the valleys of Lochaber to a much greater height than the levels of the roads, as shown by the markings, striæ, and boulders far above them. Including the lines forming the