184 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



dips at 70° to 75° to S. 27° E., or S. 33° E., and thus still conform- 

 able to the mica-slate. The lower beds are compact, glossy, blue 

 slates of uniform texture, and with a few grains of pyrites ; the 

 higher beds are a similar rock, but of a light grey or green colour. In 

 his section of this place Mr. Sharpe indicates two planes of division in 

 these slates — one of cleavage or foliation, the other of bedding or 

 deposition, but both nearly coincident. So far as I could make out, 

 the bedding and cleavage coincide, though there are other division- 

 planes dipping about 38° to N. 75° W. 



Beyond the clay-slates coarse greywackes again appear, dipping 

 first at 70° to N. 12° W., and soon at 70° to S. 17° E. There is 

 thus in this place probably an anticlinal fold in the beds, and some 

 thin irregular veins of a white granite also mark it out as an axis 

 of disturbance. About a mile further down the lake, beds of reddish 

 greywacke appear to dip at 40° to N. 10° W., but are not very dis- 

 tinctly seen. The cause of this change in the dip is probably the in- 

 trusion of a coarse red granite or felspar-rock, which breaks out near 

 the junction with the Red Sandstone, about half a mile from the Old 

 Manse. Some hard, jaspery masses associated with this igneous rock 

 are perhaps altered beds of the Old Red. Near Auchmar an impure 

 yellow limestone has been wrought, also probably a portion of the 

 Old Red, though often conjoined with the Leny limestone in the 

 clay- slate. At the Pass of Balmaha the conglomerate of the Old Red 

 Sandstone, dipping at 60° to S. 45° E., forms a bold projecting hill 

 in front of the primar} r mountains. The low ground to the south 

 consists of finer-grained red sandstone lying at a low angle, and near 

 Drymen dipping at 12° to E. 15° S. 



In this section, though the beds dip at much higher angles, the 

 relation of the formations is still the same as on the Gareloch. The 

 mica-slates, dipping south, are covered by an upper group of blue and 

 green clay -slates and greywackes. The two formations also appear 

 to be conformable, and the direction of the beds varies little from E. 

 and "W. by compass (E. 27° N. true), but near the south margin 

 of the clay-slate, probably from the intrusion of the granite, ap- 

 proaches nearer to the true east and west (E. 16° N"., to W. 16° S.)*. 



6. Callander and Pass of Leny. — Passing again to the eastward, 

 over an interval of about fifteen miles, we reach the well-known 

 vicinity of the Trossachs and Callander. To the north of the latter 

 the rocks are very well exposed in the Pass of Leny and on the banks 

 of Loch Lubnaig (fig. 3). 



At Callander, the red sandstone and conglomerate, which form the 

 low undulating plain stretching south to the Ochils,rise up into a range 

 of low but rugged hills, immediately behind the village. The rocks 

 are well seen in a fine natural section at Bracklyn Falls, where the 

 Keltie forces its way through the upturned beds in a series of deep 

 pools and whirling caldrons. Higher up the stream there is a thick 



* My observations agree generally with Mr. D. Sharpe's section in Quart. Journ. 

 Geol. Soc. vol. viii. (1852), p. 129. Sir R. I. Murchison and Mr. Geikie, in their 

 new Sketch-map, also give a section of this locality, but differing in some im- 

 portant points. 



