﻿NIC0L— N.W. HIGHLANDS. 



rected as to details by that now given* 

 (fig. 2). Beginning at the western extre- 

 mity, the magnificent promontory of Par-out 

 Head, 315 feet high, consists from top to 

 bottom of fine-grained white or light- 

 coloured mica-slate, in thin even beds. The 

 dip is from 20° to 25°, or rarely 35°, to E. 

 35° Si at the Head ; but near Old Castle 

 Point, where the rock is also darker in co- 

 lour, always to the north of east (E. 25°-35° 

 ST.). From the regular dip of the beds, the 

 thickness of this mass of mica- slate must be 

 above 2000 feet if the section is unbroken, 

 and not less than 1000 feet if a fault occurs 

 between Far-out Head and Old Castle Point. 

 In mineral character it is quite identical 

 with the mica-slate on the east of the quartz - 

 ite at Emboli, and with the mica-slate of 

 Mclness on the Kyle of Tongue. It has on 

 this account been said to overlie the Durine 

 limestone ; but, after repeated careful exami- 

 nation of the sections, which are most clearly 

 exhibited on the coast, I have been unable to 

 detect the smallest trace of limestone below 

 the mica-slate, or of mica-slate above the 

 limestone. It seems impossible to believe 

 that a mass of mica-slate, at least 1000 feet 

 thick, could have been so thoroughly swept 

 away from the surface of the limestone-field 

 for many miles in extent, had it ever existed 

 above it. 



!N"ear Balnakeil and Sangoe Bay the mica- 

 slate appears to dip under the limestone ; 

 but, as shown in the section, it is cut off from 

 it by a fault. This limestone forms a great 

 contorted mass, 128 feet high, and is in many 

 parts a red-coloured breccia ; but it dips on 

 the whole to the S.E. The brecciated struc- 

 ture is due to a mass of hornblende-rock or 

 serpentine which rises up in Sangoe Bay, 

 bringing with it portions of altered quartzite 

 and mica-slate. The igneous and metamor- 

 phic rocks extend south to Loch Calladale, 

 and have evidently been forced up through 



* The sections in the following paper run generally 

 from west to east, and, for more ready comparison, 

 are all drawn as seen from the south. The directions 

 in this paper are also true, having been corrected 

 for the magnetic variation, which in Sutherland is 

 about 29° W. 



