﻿1861.] HARKNESS HIGHLANDS AND N. IRELAND. 



263 



result of one of those contortions, exceedingly common in the rocks of 

 more eastern parts of the Highlands, which have originated from the 

 influence of those great masses of plutonic rocks so abundant in these 

 portions of the Grampians. 



§ 6. Sections from the South Side of Ben-y-Gloe Mountains and 

 Strath Ardle (fig. 5). — On leaving Blair and passing in the direction 

 of the southern flanks of the Ben-y-Gloe Mountains, a moory area is 



Fig. 5. — Section from Ben-y-Gloe Southward. Distance 3 miles. 



S. Gairnog. Ben-y-Gloe. N. 



d c d c a 



d. Gneiss. c. Limestone. a. Quartz-rock. 



traversed, which affords at irregular intervals exposures of dark- 

 coloured gneiss, dipping S.E., or from the Ben-y-Gloe range. This 

 gneiss is well seen in the course of the Gairnog stream, which enters 

 the Gary near Killiecrankie. At the shepherd's house near this stream, 

 on the road over the hills from Blair into Strath Ardle, these gneissose 

 rocks dip S.E. at 45°, and are seen overlying limestone. To the 

 north of this parallel of limestone, black gneiss again occurs, having 

 the same inclination, and is found reposing on limestones which are 

 well seen in the escarpments which, lie between the small Loch 

 Vallean on the south and the Ben-y-Gloe Mountains on the north. 

 The relations which these limestones bear to the quartz-rocks of the 

 Ben-y-Gloe Mountains are not seen, as the sides of the latter moun- 

 tains afford only debris of quartz-rocks, and along the stream- 

 courses which drain their south flanks, no exposures of rock in situ 

 are visible. It is probable that the connexion between the lime- 

 stones and the quartz-rocks of Ben-y-Gloe is cut off by plutonic 

 masses ; for we find the water-shed which separates the Gairnog from 

 Alt-Clunie, a stream flowing into Strath Ardle, to be composed of 

 coarse-grained syenite ; and rocks of a plutonic character are exten- 

 sively developed along the southern margins of the great mass of 

 quartz- rocks which occur in this portion of the Highlands, although 

 no indications of such rocks are laid down in any geological map of 

 this portion of Scotland. From Alt-Clunie, below the syenitic area, 

 gneissose rocks occur, inclined at a very high angle towards S.S.E. 

 These soon become perpendicular, and then dip 1ST.W. On the west 

 they form the great mass of Ben Bhrackie ; and from their southern 

 slopes we have, at Clunie, the limestone band of Pitlochrie again 

 making its appearance. 



This parallel of limestone, which has a N.W. dip, and which I 

 regard as a continuation of that seen on the north side of Loch Tay, 

 extends itself still further eastwards ; it has been worked at the 

 Market Muir, about half a mile N. of the village of Kirkmichael. It 

 is now wrought two miles E. of Kirkmichael, at Dunien, where it is 



