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A QUARTER of a century ago the thoughts of geologists in this country were turned more earnestly than they had ever been before to the great problems of topography, and more particularly to the origin of valleys. In 1862 Jukes published his memorable paper on the River-Valleys of the South of Ireland, which may be regarded as the starting-point of all subsequent research on the subject. The following year there appeared the first edition of the Physical Geology and Geography of Great Britain, by my former colleague and chief, Sir Andrew C. Ramsay, wherein the potency of denudation as a factor in the evolution of scenery was ably maintained. Papers enforcing similar doctrines were given to the world by my colleagues, Dr. Foster, Mr. Topley, and Mr. Whitaker. Though these views were only a reiteration and more detailed elaboration of the principles laid down by Hutton and Playfair, and were acknowledged to be so by those who espoused them, they encountered much opposition. It was whilst the controversy they evoked was in full force that the first edition of the present volume appeared-in 1865.

The two and twenty years which have slipped away since then have witnessed a great change in the attitude of geologists towards questions of topography. The views which, in concert with my colleagues in the Geological Survey, I had been led to adopt from close and constant examination of the evidence, are now accepted as part of the general stock of geological knowledge. For this recognition it is a pleasure to admit that they are largely indebted to the powerful and independent support they have received from the labours of the geologists who, following in the wake of my honoured friend, the veteran Newberry, have, during the last twenty years, been exploring the western regions of the United States. Had the question in dispute been first studied in that marvellous country of mesas and cañons, there would never have been any discussion about it. The truth is there proclaimed with an impressiveness almost bewildering to one whose experience has chiefly lain among the more ancient and convoluted rocks of Western Europe. All the more honour, therefore, to those who found the solution of the problem in the much less favourable field of European geology

Since this work first appeared a large part of my time has been devoted to a further study of the history of scenery. My official duties have enabled me to pursue the examination of the evidence into the nooks and corners of almost every parish in Scotland. I have carried the investigation into many parts of Europe from the north of Norway to the plains of the Danube. But above all, it has been my good fortune to have been able to extend the research into Western America, and to have learned more during my months of sojourn there than during the same number of years in the Old Country.

The result of this accumulated experience has been to convince me, if possible, more firmly than ever, of the soundness of the principles for which I contended in the first edition of this book. Many years ago the volume was out of print, and I have been repeatedly urged to allow it to be reprinted in its original form. But though the principles remained unchanged, my knowledge of the country had become so very much wider and more detailed that it seemed best to wait until such leisure came as would allow the fruits of this enlarged experience to be made use of in the book. I have now at last been able thoroughly to revise, and in large measure to rewrite the old chapters, adding greatly to them, but retaining the descriptive passages, which still remain, I hope, faithful pictures of the scenery they attempt to portray. With the exception of a few reductions from photographs, which will at once be recognised, the woodcuts are taken from my own sketch-books, and I have to thank Mr. J. D. Cooper and Mr. O. Lacour for the skill and labour they have bestowed on their task. The Geological Map represents, as far as one on so small a scale can do so, the present state of our knowledge of the general geology of the country. To my colleague, Mr. B. N. Peach, I am indebted for the Section No.I.on the Map, representing in diagrammatic form the geological structure of the North-West Highlands. This diagram shows in more detail than has hitherto been published the extraordinary structure of that region as worked out during the detailed investigation of the Geological Survey. I have to thank Mr. Peach also for important help in the preparation of the Map of the Glaciation of Scotland.

In one important respect the present differs from the former edition. I have drawn up an Itinerary of routes through the country, with the view of guiding the traveller to those features which are of greatest interest in regard to the questions discussed in the book.

Two and twenty years are a long part of a human life, and never fail to bring their sad retrospect of memories. The first edition of this volume was dedicated to my honoured chief and large-hearted friend, Sir R. I. Murchison. He has been for sixteen years gathered to his rest, but I shall never cease to miss his sympathetic help and wide experience to which on every occasion I was free to turn. His successor, Sir A. C. Ramsay, with whom during the

writing of the first edition I had so many profitable discussions, has retired to his beloved Wales, after a long and distinguished career. Jukes, who led us all in the new crusade, has long been dead. Scrope, the gentle and sagacious adviser and helper of younger men, who more than half a century ago proclaimed the truth about the origin of valleys, has passed away. Lyell too, and Sedgwick, and Phillips, and others, to whom twenty-two years ago we looked up with such veneration and affection, have one by one disappeared. There is a melancholy pleasure in thus once more associating the names of these leaders with a little volume in which they were pleased to take an interest.


4th July 1887.

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