1852.] 



SHARPE ON THE HIGHLANDS. 



129 



•^PS -c 



is thrown up both 



VOL. YIII. PART 



slate. This is overlaid to the northward by the 

 chloritic or "green slate," which dips N. 20° 

 W. 65°, where it overlies the clay-slate, but at 

 the side of Loch Dow is suddenly turned up 

 with a dip of S. 20° E. 50° to 70°, and farther 

 north, on the side of Loch Chon, rests imme- 

 diately on mica -schist. Some of the beds of 

 green slate are full of small quartz-pebbles. 



To the eastward of this section the green 

 slate is well seen in the Trossachs, and also be- 

 tween Callander and Loch Lubnaig, on both 

 which sections it covers a breadth of three or 

 four miles. The beds of slaty quartzose con- 

 glomerate are of great thickness, and pass 

 downwards on its southern edge into a coarse 

 slaty greywacke, which may be seen both at the 

 head of Loch Vennachar and at the falls of the 

 Leny, resting on greenstone-trap, which bounds 

 the slates southwards. According to Mr. Nicol*, 

 the clay-slate runs through both Ben Ledi and 

 Ben Venue, where it must come up between the 

 green slate and the mica-schist. 



To the westward of Loch Chon the green 

 slate is interrupted by the upheaval of the mica- 

 schist of Ben Lomond, which throws the band 

 of slates several miles south of the course it 

 follows to the eastward ; but the dark clay-slate 

 continues from near Aberfoyle to the Ross point 

 on the west side of Loch Lomond, where it 

 dips S. 20° E. 65°, and rests on the mica-schist, 

 being overlaid farther south by the green slate, 

 as is seen in fig. 3. 



The section of the east side of Loch Lomond 

 (fig. 3) is very clear and instructive. From the 

 head of the lake to the Cullimore Burn, f of a 

 mile below Rowardennan, the side of the lake 

 (including Ben Lomond) is formed of mica- 

 schist : this is overlaid by clay-slate, forming 

 a band about a mile wide, and dipping S. 20° E. 

 65° to 70°. This is overlaid on the south by 

 the green slate, which covers about four miles of 

 the side of the lake, and is arranged in a great 

 synclinal axis, as on the Aberfoyle section ; but, 

 instead of our finding the clay-slate rising from 

 below the southern edge of the green slate, as 

 at Aberfoyle, the green slate meets the Old Red 

 Sandstone about f of a mile north of Balmaha. 

 The lower part of this green slate series, which 

 at its northern and southern edge, includes 

 * Loc. cit. p. 149. 



I. K 



