Sept. 10, 1885 | 
NATURE 
459 
occasion, he challenged his old friend Nicol to meet him at the 
forthcoming meeting at Aberdeen to discuss the question, and 
the challenge was accepted. 
When Murchison arrived at this city, in September 1859, he 
brought with him a redoubtable champion in the person of Prof, 
(now Sir Andrew) Ramsay, the director of the Geological Sur- 
vey, who had been conducted to Assynt and shown the section 
there. It may perhaps serve as a caution against hasty general- 
isations, drawn from a single section imperfectly examined, to 
remember that so excellent a field-geologist as Ramsay un- 
doubtedly was not only failed to see the weakness of Murchison’s 
position, but threw all the weight of his great authority into the 
scale against Nicol in this memorable controversy. 
Nicol, however, laid before this meeting a paper which, after- 
wards published in detail in the Fouwrnal of the Geological 
Society,! must be admitted to have really established the main 
facts concerning the geology of the Highlands as accepted by all 
geologists at the present day; though his views, as is not un- 
commonly the case with great and original discoveries, were met 
for a long time with nothing but bitter opposition or cold neglect. 
Permit me to state, as briefly as possible, the conclusions which 
Nicol, as the result of three years of patient work in the 
Western Highlands, was able to announce in this place, just 
twenty-six years ago. 
1. He maintained with Macculloch and Hay Cunningham, 
and in opposition to the views originally propounded by Sedg- 
wick and Murchison, that there exists in the Western Highlands 
an enormously thick series of red sandstones, quartzites, and 
limestones, which rest unconformably upon the ancient gneisses 
and schists, and belong to a far older geological period than the 
Old Red Sandstone. 
2. He showed that this series of strata really constitutes ¢wo 
distinct formations, and that the older of these, the Torridon 
Sandstone, consists of red sandstones and conglomerates, in 
which no organic remains could be detected. 
3. The younger of these formations was shown by him to lie 
unconformably upon the Torridon Sandstone, and to consist of 
three members, which Nicol named the Quartzite, the Fucoid 
Beds, and the Limestone (Quart. Fourn. Geol. Soc. vol. xvii., 
1861, p. 92, &c.). It is this formation which has yielded the 
interesting fossils of Lower Palzeozoic age. 
4. The apparent repetition of beds of quartzite and limestone, 
which was insisted upon by Murchison, was shown to be due to 
faulting and overthrow, and thus the ‘‘ Upper Quartzite ” and 
the “‘ Upper Limestone” of that author were proved to have no 
real existence (Quart. Fourn. Geol. Soc. vol. xvil., 1861, pp. 
98, 108, 109, &c.). 
5. What so many authors had taken for a conformable up- 
ward succession of this older Palaeozoic formation into overlying 
schist and gneiss, was asserted by Nicol to be an altogether 
fallacious appearance, due to the thrusting of the crystalline 
rocks over the sedimentary ones by great overthrow-faults. 
6. The relations between these crystalline and sedimentary 
strata in the Scottish Highlands were shown to be precisely 
similar to those which are constantly produced by lateral pressure 
in all great mountain-chains, and consist of sharp foldings, in- 
versions, and faulting on the very grandest scale. Examples of 
overthrow-faults, similar to those of the Scottish Highlands, were 
instanced by Nicol as occurring in the Alps (Quart. Fourn. 
Geol. Soc. vol. xvii., 1861, pp. 108, 109, IIo). 
We cannot perhaps better illustrate the position maintained by 
Nicol in this remarkable paper than by quoting the following 
passage: ‘‘ Until some rational theory is produced of the mode 
in which an overlying formation, hundreds of square miles in 
extent and thousands of feet in thickness, can have been meta- 
morphosed, whilst the underlying formation of equal thickness 
and scarcely less in extent has escaped, we shall be justified in 
admitting inversions and extrusions” (z.e., of older masses on 
younger, as he explains his meaning to be) ‘‘ equal to those of 
the Alps” (Quart. Fourn. Geo!. Soc. vol. xvii., 1861, p. 110). 
The only serious error into which Nicol fell—and after all it is 
a very inconsiderable one judged in comparison with his un- 
doubtedly great achievements—was that of attaching too much 
importance to the influence of igneous intrusions in connection 
with the tremendous inversions and overthrow-faults to which he 
so clearly showed that these Highland rocks have been subjected. 
We now know that many of these supposed intrusive masses, 
1 Quart. Journ. Geol. Soc. vol. xvii., 1861, pp. 85-113. _This paper was 
read on December 5, 1860; although its title is slightly differen:, the whole 
course of the argument is the same with that of the paper read here in the 
September of the previous year. 
though really of igneous origin in all probability, were of o/der 
date than the Palzozoic rocks in the midst of which they lie ; 
and that they were brought into their present positions, not by 
intrusion in a liquid state, but by complicated faulting. It must 
be remembered that these ‘‘granulites,” as Nicol very justly 
called them (Quart. Fourn. Geol. Soc. vol. xvii., 1861, 
p- 89) for they present a wonderful analogy with the typical 
rocks of Saxony which are known by that name, have long been 
regarded by geologists as among the most difficult and perplexing 
of rocks to explain the orizin of, though the recent researches of 
Dr. Lehmann have now done something towards the solution of 
the problem. 
Calmly reviewing, in the light of our present knowledge, the 
grand work accomplished single-handed by Nicol, I have no 
hesitation in asserting that when this Association met here 
twenty-six years ago, he had already mastered the great Highland 
problem in all its essential details, and that his results were 
distinctly proclaimed during the meetings of this section. 
If, then, Nicol had so fully solved this great problem of 
Highland geology twenty-six years ago, how is it, may not un- 
reasonably be asked, that we have waited so long for the justice 
of these views to be admitted ? 
A variety of circumstances have contributed to bring about this 
unfortunate result. Murchison was at the time too old and 
infirm to examine in careful detail the wild districts where those 
rock-masses are exhibited. Hence Nicol’s oft-repeated invita- 
tions to view the sections in his company remained unheeded, 
and we find the great geologist of Aberdeen writing in 1866 his 
concluding plaintive words in this memorable discussion: ‘I 
must express my most sincere regret that my illustrious opponent 
—from whom only the most thorough conviction that my views 
are well founded, and that the question was one on which it 
became a teacher of geology in Scotland to give no uncertain 
utterances, could have compelled me to differ—has never found 
it convenient to meet me again in the North. Iam convinced 
that we agree in so many essential points, that a few hours 
together in the field would bring us nearer in opinion than 
whole volumes of controversy.” (‘‘Geology of the North of 
Scotland, p. 96.”’) 
The phalanx of eminent geological authorities opposed to the 
views of Nicol, including Professors Harkness, Ramsay, Archi- 
bald Geikie, and Hull, for a long time carried all before them ; 
but it is now admitted that each of these excellent observers was 
deceived by having seen only portions of the evidence, and that 
they based their conclusions on imperfect data. Nicol, though 
during the later years of his life he declined unavailing coa- 
troversy, still continued to study the Highlands year by year, re- 
examining every joint in his armour and satisfying himself of its 
soundness. 
In the year 1877 I had an opportunity of visiting for the first 
time the interesting sections of Assynt and Loch Broom, in 
company with Dr. Taylor Smith, F.G.S., and Mr. Richard D. 
Oldham, now of the Geological Survey of India. Although I 
entered upon this task with the strongest prepossessions in 
favour of the Murchisonian hypothesis, yet what I saw there 
during several weeks of work convinced me that the theory of 
an ‘* Upper Quartzite” and an ‘‘ Upper Limestone” was alto- 
gether untenable, and that, so far as these two sections were 
concerned, Nicol’s interpretation was undoubtedly the correct 
one. I was greatly impressed with the proofs of enormous 
folding and faulting among these Highland rocks, and when, 
shortly afterwards, 1 had an opportunity of meeting Prof. Nicol 
in this place, and of hearing from his lips many details of his 
later work, I strongly urged him to republish his conclusions 
with the fuller illustrations and arguments which he was then so 
well able to supply. To all my pleadings he made but one 
reply: important as he knew these discoveries to be, yet in his 
advancing years he thought but little of the glory of them com- 
pared to their painful consequences to himself—the breach of the 
old friendly relations with one he, to the end, so greatly loved 
and honoured. He strongly deprecated at that time the re- 
opening of a controversy associated for him with such bitter 
memories ; but he expressed his full conviction that when suffi- 
ciently accurate topographical maps were in existence, and the 
whole district should be surveyed by competent geologists, the 
truth of all the essential parts of his teaching would be 
established. ! 
1 In my two earlier papers ‘On the Secondary Rocks of Scotland,” 
published in 1873 and 1874 respectively, I had employed the Murchisonian 
nomenclature for the older rocks of the Highlands whenever I had occasion 
