1865.] JAMIESON EAST CHANGES IN SCOTLAND. 165 



markings, and the perfection in which they are to be seen, depend 

 greatly upon the quality of the rock, and the circumstance of its 

 having been well covered with clay so as to preserve the traces 

 from obliteration. In the north and west Highlands the markings 

 are more frequent and striking than elsewhere. Along the rocky 

 shores of the west coast they may be studied with great advantage — 

 as at the Gareloch, Loch Fyne, Ballachulish, and many other places. 

 On the other hand, there are wide districts, as in Fife and the low 

 north-east part of Aberdeenshire, where it is rare to find them ; 

 and it is only by keeping a look-out where quarries are opened, or 

 railway-cuttings and such like works are in progress, and a fresh 

 surface is thus exposed to view, that they are to be seen. 



In the open country, and on the tops of ridges, the direction of 

 the furrows is generally very uniform over wide districts ; but in 

 the deep mountain-valleys it conforms, as a rule, to the direction 

 of the glen. Taking the country as a whole, we find, on coming 

 to map the markings, that they radiate from the chief mountain- 

 masses of the interior, and that the rubbed faces of the rocks look 

 towards the great watersheds. 



The group of hills stretching from Ben Lomond towards Ben 

 Nevis, and from that mountain eastward to the sources of the River 

 Dee, forms one line from which the erosive agent seems to have 

 descended. Another lies along the watershed that extends from 

 the head of Loch Arkaig northward to Loch Shin, and from that 

 eastward to the Ord of Caithness, as shown in the little map accom- 

 panying this paper. 



In a former contribution to the Journal of the Society (vol. 

 xviii. p. 164), I have given my reasons for thinking that this 

 remarkable action upon the surface of the country has, in the 

 great majority of instances, been caused by land-ice moving down- 

 ward and outward from the chief mountain-masses of the interior. 

 Along these lines, when the ice was at its greatest development, 

 there seems to have been an immense accumulation, not merely in 

 the hollows and valleys, but even along the whole crest and centre 

 of each ridge ; and from each of these Hnes the ice seems to have 

 flowed off, not in a multitude of separate glaciers, but in one wide 

 and connected stream. At the same time I do not mean to deny 

 that there has been some scratching by means of floating ice. 



All the facts are in harmony with the notion that the ice was of 

 enormous thickness. Thus the detached mountain of Schihalhon in 

 Perthshire, 3500 feet high, is marked near the top as well as on 

 its flanks — and this not by ice flowing down the sides of the hill 

 itself, but by ice pressing over it from the north. On the top of 

 another isolated hill, called Morven, about 3000 feet high, and 

 situated a few miles to the north of the village of Ballater, in the 

 county of Aberdeen, I found granite -boulders unlike the rock of 

 the hill, and apparently derived from the mountains to the west. 

 Again, on the highest watersheds of the Ochils (a range of trap- 

 hiUs stretching from Stirling towards Perth), at altitudes of about 

 2000 feet, I found this summer (1864) pieces of mica-schist full of 



