Page:Popular Science Monthly Volume 43.djvu/271

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fame. To his aptitude in this application Nature largely ascribes the success of his more popular works, which, it says, "will be easily understood if we remember that in Sir Archibald's works the traditional barrenness of geology is always smoothed and adorned by a deep and intense feeling for Nature. Nobody has done more than he to associate geological science with the appreciation of scenery." Mr. G. K. Gilbert, in a review of his TextBook of Geology, remarks as a single departure in the volume the elevation of physiographical geology to the rank of a major division. "The same title, it is true, has been placed by Dana at the head of a primary division of the subject, but it was used by him in a different sense. With Dana it is a synonym for physical geology; with Geikie it is 'that branch of geological inquiry which deals with the evolution of the existing contours of the dry land.' So far as the subject has had place in earlier treatises, it has been regarded as a subdivision of dynamical geology, and the classification which placed it there was certainly logical. In dynamical geology, as formulated by Geikie, the changes which have their origin beneath the surface of the earth (volcanic action, upheaval, and metamorphism) and the changes which belong exclusively to the surface (denudation and deposition) are separately treated. In physiographical geology the conjoint action of these factors of change is considered with reference to its topographical results. Starting from geological agencies as data, we may proceed in one direction to the development of geological history, or in another direction to the explanation of terrestrial scenery and topography, and if the development of the earth's history is the peculiar theme of geology, it follows that the explanation of topography, or physiographical geology, is of the nature of an incidental result—a sort of corollary to dynamical geology. The systematic rank assigned to it by Geikie is an explicit recognition of what has long been implicitly admitted—that geology is concerned quite as really with the explanation of the existing features of the earth as with its past history."

The subject was first formally presented from this point of view in the Lectures on the Scenery of Scotland viewed in Connection with its Physical Geology, which were delivered in 1865. At this time, as Mr. A. H. Green remarks in his review of a new edition of the lectures in 1887, the controversy respecting Hutton's theory of denudation as the main and most efficient agency in shaping the earth's surface was at its height. The author acknowledged in the preface to his second edition that his views when first published ran directly counter to the prevailing impressions on the subject; but now, after a lapse of twenty-two years, they were accepted as part of the general stock of geological knowledge. "How largely," Mr. Green says, "this result is