Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHAPTER III THE ALPS AND THE GERMAN DANUBE An attempt was at one time made to explain the formation of mountains by the hypothesis of perpendicular upheavals along straight lines. Of all mountains the Alps can least be made to accord with such a theory. Their great curve taking every conceivable direction, first led to the recognition of the characteristics that mark a one-sided, folded mountain chain :—the movement from the inner side of the curve, the thrusting forward of the fold towards the outer edge, the encroachment of that edge upon the land beyond, the arresting power of old blocks of upland, and, on the other hand, the fracture of strata on the inner side, the formation of long lines of crevasse, and the drop of great areas of depression to form the plain of the Po. But the Alps also taught us how great a part in developing the physiognomy of mountains is played by the destructive forces of the atmosphere. The action of the atmosphere, by carrying away great layers of Jurassic and Triassic limestones, and so denuding the highest mountain belt of its more recent covering formations, has imparted to the scenery of the Alps one of its most characteristic features, the exposure of a broad Central Zone of very ancient rocks—granite, gneiss, and crystalline schists. It may be calculated that at one time a mass of deposits more than 6000 feet thick arched over the mighty massifs of the central zone, and that but for denudation the Alps would rear their heads to a height of above 20,000 feet. At more than one point, in crossing the watershed of the Alps, we may still behold light grey caps of Triassic or Jurassic limestone crowning the highest points above us.In the Grisons, indeed, we may cross from the Rhine to the Engadine, and from the Engadine into the neighbourhoo...