MOUNTAIN GLORIES.°
WE are grateful to any writer who helps us to understand the glory of the mountains : and no one is better qualified to undertake this task than Professor Geikie. Mountains, as Ruskin said, are the " great cathedrals of the earth, with their gates of rock, pavements of cloud, choirs of stream and stone, altars of snow, and vaults of purple traversed by the continual stars." Professor Geikie rightly protests against the folly of those sentimentalists who fear that a study of the anatomy or structure of mountains may diminish our appreciation of their scenery—much as Mark Twain thought that a doctor could see only a hectic flush where the ordinary man was content to admire an exquisite complexion. The more we know, the more competent wo are to admire justly. Ruskin, unquestionably the best describer of the mountains. often regretted that he had not devoted his life to geology rather than art. "It is true that the geologist is not so free as others to let his fancy roam, and to indulge in vague dreams as to the birth of mountains. He may talk of a tumbled sea of mountains, but that is only a figure of speech : he does not really believe with the poets that some great convulsion has tossed the crust into heaving billows, that beetling cliffs and serrated ranges are the crests of mighty earth-waves suddenly arrested in their mad career. . . The features which most impress artists and poets are of secondary origin."
Professor Geikie tells us that all bills and mountains, not- withstanding the vast range of their dimensions and the infinite variety of their forms, may be classed tinder one or other of two great divisions—Original or Tectonic, and Sub, sequent or Relict mountain.. Among Original mountains must be included every height which owes its genesis either to (1) the piling or heaping of materials at the surface ; or to (2) subterranean action which has resulted in the folding or rupturing of the earth's crust. To the former subdivision belong all volcanic cones, active or extinct, such as Popo- catepetl and Vesuvius, North Berwick Law and the Puy de Dome; and also all the sandhills and moraines so common in Scotland and Northern Europe. The latter subdivision include. practically all the great mountain chains of the world, of which the Alps present the most familiar and the Himalayas the most gigantic example. Most of these chains have been produced by more than one long-continued lateral thrust, heaving up the earth's cruet in huge permanent folds, which the forces of denudation have carved into the shapes now visible. Subsequent mountains have come into existence in quite a different fashion. They have neither been built up like volcanoes or sandhills, nor do they owe their existence directly to deformation of the earth's crust. Their most characteristic representatives are remnants of older and more extensive high grounds or plateaus. These tablelands have been shaped into crag and precipice, alp and valley, by the steady work of the various instruments of erosion—wind and water, frost and snow. A good example is to be found in the picturesque heights of Saxon Switzerland, which have thus been hewn out of Mesozoic sandstones, arranged in approximately horizontal beds. Other examples are the cation region of Colorado and the basalt bills of Antrim and the Inner Hebrides—" mere wrecks of a great plateau of accumulation." Throughout the Highlands, indeed, "Nature's saws and chisels" are more in evidence than her convulsive wriggling. Numerous excellent photo- graphs of typical mountain scenery illustrate Professor Geikie's admirable text-book.
• Yowttaias: Altair Origin; Gesath,and Dopey. By Jame' (bUcht. DV.466zsb6
Oliver sod Boyd. [12a. 64. Data •
Previous page
