﻿258 



PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



[Feb. 20, 



Again, in the same memoir, with reference to Jura, alluding to 

 the gheissose rocks, he states that these are " apparently super- 

 imposed on the quartz-rock* ;" and yet, after using the word appa- 

 rently as though this was not the true position, he goes on (at p. 456) 

 to quote Prof. Jamieson, who says that " quartz -rock rises at an 

 angle of 45° from under micaceous schists." 



The same idea as to primitive and transition seems to have been 

 the leading feature in his mind with relation to arrangement when 

 he visited Glen Tilt ; and yet, when he comes to describe definitely 

 the sequence of rocks here, we generally find that his statements 

 are hostile to his preconceived ideas. 



These general observations will serve as a prelude to what I 

 have to add to the geology of portions of the Highlands lying south 

 of the Caledonian Canal ; and, as these observations have reference 

 to purely physical geology, I shall proceed to describe the several 

 sections, and afterwards the general results obtained therefrom. 



Fig. 1. — Section from Callender to Loch Earn. Distance 9 miles. 



'' Callender. Woodhead. Anneehaugh. Ardchullarie. Kuskin Burn. 



e a oc d d d c . d 



e. Old Red Sandstone. d. Gneiss. c. Limestone. b. Shale. 



a. Quartz-rock. # Trap-rocks. 



§ 2. Section from CaUender to Loch Earn (fig. 1). — In the imme- 

 diate neighbourhood of Callender, deposits belonging to the Old Ked 

 Sandstone series are extensively developed. At the distance of 

 about a mile and a half to the N.W. of the village, the great 

 line of fracture separating the rocks of this age from the meta- 

 morphic strata of the Grampians is seen. In Leny Glen the point of 

 contact between the rocks appertaining to these different series is ex- 

 hibited, the rocks of the Old Red series appearing in the form of 

 conglomerates ; immediately on the N.*W. of them, above the line 

 of fault, quartz -rocks, referable to the older deposits, occur; and 

 upon the small development of the quartz-rocks here seen, black 

 shales are found reposing conformably. These quartz -rocks and 

 black shales dip towards the N.N.W. On leaving this glen and 

 continuing the section on its rise, we have, at Leny lime-quarry, 

 the same black shales manifested, dipping N.N.W. at 35°, and 

 possessing an anthracitic aspect, which allies them in lithological 

 nature with the anthracitic shales of the Lower Silurians of the 

 South of Scotland. In these black shales, which from their nature 

 might have afforded abundance of Graptolites, no fossils were ob- 

 tained. Resting conformably on these shales, a thin layer of lime- 

 stone is seen, of a dark grey colour, regularly bedded, but contorted, 

 and abounding in white veins of carbonate of lime. This limestone, 

 which also afforded no fossils, and which has a thickness of about 

 eight feet, is succeeded by grey clay-slate, in some instances wear 

 * Geol. Trans., vol. ii. p. 454. 



