TRANSACTIONS OF SECTION C. 1003 
distant Paleozoic period. Nowit is not only dead, but stretched on the dissecting- 
table of the geologist—its outer integuments and softer tissues stripped away, and 
its very skeleton bared to our view—a splendid ‘ subject’ for the student of moun- 
tain anatomy. 
One of the first to recognise this value of our Scottish Highlands to the student 
of Orographic Geology was the late Daniel Sharpe. He had made himself familiar 
with many of the characteristic details of Alpine architecture—so far as it was then 
understood—and was able to show that the foliated masses of our Highland dis- 
tricts exhibit precisely those relations which would be seen if the contorted and 
fan-like masses of the Alps were planed away by denudation. Nor in suggestions 
of this kind, as we have seen, was James Nicol far behind Sharpe ; but at that time 
many of the most important features of mountain-structure were unrecognised or 
misinterpreted, and the conclusions of these geological pioneers were little more than 
guesses—though very valuable and suggestive guesses— after truth. 
It is to our geological brethren over the Atlantic that we are especially indebted, 
not only for many important discoveries in the mechanics of mountain-formation, 
but for clearing away many of the clouds of error in which the subject had become 
involved. To Henry Darwin Rogers, who, after a career of valuable geological 
work in his native State of Pennsylvania, accepted the hospitality of this country, 
and spent the last decade of his useful life as Professor of Natural History and 
Geology in the sister university of Glasgow, must be assigned the foremost place in 
that school of orographie geologists which has grown up in America. 
The first sketch of the important theory of mountain-building, to which Rogers 
and his fellow-geologists were led by the study of the Appalachian chain, was 
published in 1842, but it was not till 1858 that the complete evidence on which 
this theory was founded could be published. 
The conclusion at which Rogers arrived was, briefly expressed, as follows :— 
The Appalachian mountains were carved by denudation out of an enormously 
thick mass of stratified deposits, thrown into a series of parallel wave-like folds. 
To the westward of the mountain range ‘the crust-wavyes flatten out, recede from 
one another, and vanish into general horizontality ;? but towards the heart of the 
mountain-mass the same flexed strata become greatly crowded together, their ‘ axis- 
planes’ become more and more inclined, till at last their folds, yielding at their 
apices to the tremendous lateral thrust, fractures twenty to eighty miles in length, 
and attended with a displacement of 20,000 feet or more, were produced. 
Unfortunately Rogers accompanied these just views of mountain structure with 
certain crude speculations and untenable hypotheses concerning the methods by 
which they were produced. But inthe minds of other American geologists, among 
whom may especially be mentioned Dana, Le Conte, and Vose—the fruitful ideas 
of Rogers have undergone development and expansion, while they have received 
abundant illustration through the labours of that active band of pioneers—the 
United States Geological Survey—including Clarence King, Powell, Emmons, 
Hague, Dutton, Gilbert, and many others. 
Nor have the brilliant results attained by these investigators in the New World 
been without their effect on the geologists of Europe. Lory, Suess, Heim, Baltzer, 
and others have shown that the clue to the right understanding of the structure of 
the Alps, which had been so diligently sought and so long missed by Von Buch 
and De Beaumont, by Studer and Favre, was now placed in our hands by the 
researches of the American geologists. 
In Northern Europe, Kjerulf, Dahll, Broégger, Reusch, and other geologists have 
ably illustrated the same peculiarities of structure in the denuded mountain-chain 
near the southern extremity of which we are now assembled ; and in a recent 
valuable and suggestive essay ‘ On the Secret of the Highlands’ Professor Lapworth 
has shown how perfectly these structures are exemplified in the western district of 
Sutherland. 
In offering a few remarks on some of the still unsolved problems of Highland 
geology I shall not hesitate to treat, as belonging to the same geological district, 
both Scandinavia and Scotland. Not only is the succession of geological deposits 
in the two areas almost completely identical, but the characters of the several 
