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posed that great undulations in the waters under which the coal 

 strata were deposited produced by earthquakes or other elevating 

 forces, which gradually converted the area into dry land, were of 

 such energy and long continuance as to tear up and re-arrange the 

 rocky materials on the bottom to sweep off great bodies of strata, 

 forming such valleys of denudation as that of Campsie and Lennox- 

 town on opposite sides of which the strata exactly correspond 

 and that the deposits so formed were subsequently modified by the 

 action of floating ice, or the surface moulded by glaciers after the 

 whole area was converted into dry land ? Icebergs we know are only 

 formed along the sea borders of land covered with glaciers. Such 

 ice-covered land must therefore have existed along the north-west of 

 Scotland, presenting a bold coast towards the south-east, whence the 

 bergs floating off through a deep sea, deposited their rocky load as 

 they melted below and were capsized, or as they stranded on the tops 

 of sunken ridges. Thus huge masses of mica slate were left on 

 the summits of the Pentlands and Lennox hills, and the whole basin 

 of the Clyde strewed with the spoils of the Grampians, to whose 

 eastern flanks, as an old sea border, we are thus enabled to track back 

 the course of the floating bergs. The blocks are often so remarkably 

 grouped that we can almost mark the spots where successive icebergs 

 were stranded. The writer of these notices has seen in many of the 

 glens descending upon Loch Long from the west and north-west 

 successive assemblages of granite blocks, as many as 200 within a 

 circular area of 30 yards diameter, with long intervening spaces 

 almost destitute of them. The masses increase in magnitude as 

 the granite nucleus whence they emanated is approached ; and as 

 the glens become narrower and the hill sides steeper, the crowd 

 of blocks is so great as almost to fill the valley, while the rocky 

 sides exhibit grooved and polished surfaces and roches moutonntes 

 in great perfection. In the same district are many striking 

 examples of perched blocks. At heights varying from 1,200 to 

 1,800 and perhaps 2,000 feet, and on the slopes of mica schisfc 

 mountains so steep that one cannot descend but by a zig-zag course, 

 granite blocks are lodged but slightly in the thin soil, on narrow 

 ledges or terraces in considerable numbers, and of all sizes up to those 

 whose weight was carefully estimated at 1J tons. Towards the bot- 

 tom of the valleys some were estimated at 13 to 15 tons. Across 

 the deep hollow occupied by Loch Long, up the sides of the hills on 

 the east side, and across the rugged and high ridge dividing it from 

 Loch Lomond, trainees of such blocks may be followed. Near 

 Arrochar, east side of Loch Long, they are abundant and of great 

 magnitude. These facts indicate a vast amount of submergence 



