TRANSACTIONS OF THE SECTIONS. 119 



to our own. In them are found skulls with gigantic horns and huge bones of the 

 old Urus. Two fine specimens of these skulls in the Museum — one from Belhelvie, 

 another from Caithness — show the wide range of this noble species in former times. 

 And here the proper geologic history of the district ends. 



On the Relations of the Gneiss, Red Sandstone, and Quartzite i?i the North- 

 West Highlands. By James Nicol, F.R.S.E., F.G.S., Professor of 

 Natural History in the University of Aberdeen. 



The author expressed his reluctance and regret at appearing in opposition to his 

 distingushed friend, Sir R. I. Murchison. After the eloquent lecture which they 

 had listened to on Friday evening, he would willingly have remained silent on the 

 points of difference. But last year, at Leeds, Sir R. Murchison had challenged 

 him to discuss the question here, and this challenge he could not decline. The 

 question is one of far too much importance, not only in the geology of Scotland, 

 but in general theoretical geology, to be left undecided. 



Sir Roderick said the other night that he had visited this region four times 

 in order to examine this question. Prof. Nicol had also spent a considerable por- 

 tion of four summers investigating these rocks, and had traversed the whole line 

 of junction from Cape Wrath and Loch Emboli to the Sound of Sleat in Skye, 

 and examined the strata from the wilds of Lewis in the far west, to the interior of 

 Sutherland and Ross on the east. He might thus claim some knowledge of the 

 formation, and stated no facts in this paper except such as he had observed. For 

 the distribution of the rocks he referred to his recent Geological Map of Scotland, in 

 which the red sandstone of the west was first separated from the undoubted Old 

 Red Sandstone on the east coast. 



There was no difference of opinion between Sir R. Murchison and himself in 

 regard to the first steps in the series. Both were at one in regard to the order 

 established in Prof. Nicol's paper of 1856, of — 1st, Gneiss, covered unconformably 

 by, 2nd, Red Sandstone, and this by, 3rd, Quartzite, and, 4th, Limestone. But here 

 they diverge — Sir R. Murchison affirming that there is another higher quartzite 

 and limestone overlaid conformably by mica-slate and gneiss, whilst Prof. Nicol 

 states that there is here a line of fracture bringing up anew the lower beds of the old 

 metamorphic formation. In proof of this he exhibited and described various sec- 

 tions. The first, of Durness, showed on the west side in Far Out Head, mica- 

 slate identical with that on the Kyle of Tongue, then fragments of limestone, 

 interrupted by mica-slate and serpentine, then again limestone and quartzite, all 

 separated from each other by N. and S. faidts and raised up by an axis of granitic 

 gneiss, and then on Loch Emboli the quartzite and limestone, dipping west from 

 another igneous axis, throwing off beds of talc and mica-slates like those of Far Out 

 Head to the east. He showed also another section in this region, in which the 

 supposed overlying gneiss was proved to be a felspar porphyry. 



He next stated that the same relations existed at Craig na Feolin, and on Loch 

 More, where the rocks described by former observers as overlying gneiss were in 

 reality an intrusive rock ; whilst the great mass 800 or 1000 feet thick of quartzite 

 seen in Arkle on the north of Loch Stack, on the south of that Lake was represented 

 only by a few beds, and did not regain its dimensions till we reached Assynt, where 

 it has escaped denudation. The Assynt section he also showed had been greatly 

 misunderstood, the limestone of Stronchrubie being troughed by the quartzite of 

 Ben More and not dipping under it, whilst great masses of igneous rocks had been 

 wholly overlooked. 



He then explained a section of Coolmore and Craig-an-Cnockan, in which the 

 quartzite covered by the limestone was brought side by side with the gneiss on the 

 east by a faidt with interposed igneous rocks. Referring to his sections on Loch 

 Broom formerly published, and to the Loch Maree section described at the last 

 meeting of the Association, he proceeded to explain a large section of the Gair- 

 loch and Loch Torridon Mountains, in which the true structure of the country was 

 well shown. In this the quartzite was seen not only overlying but apparently 

 alternating with, and dipping under the red sandstone no less than five times in 

 a single mountain, the whole, however, as distinctly seen in the naked precipices, 

 being produced by repeated slips and fractures with enormous lateral pressure. At 



