Abstract
IN the future development of scientific geography one of the main lines of advance will be in the direction of a closer alliance with geology. The descriptions of the various countries of the globe will include an account of how their present outlines came into existence, and how their plants and animals have been introduced and distributed. The principles on which this evolutional geography will be founded have regard to the materials of which the framework of the land consists, to the various ways in which these materials have been built up into the solid crust of the earth, and to the superficial changes to which they have been subsequently exposed. The materials of the land consist mainly of compacted detritus, which, worn from previously existing terrestrial surfaces, has been laid down in the sea. Hence the land, as we now see it, has originated under the sea. But the common belief that over the whole globe land and sea have been continually changing places, and that wide continents may have bloomed even over the site of the most lonely abysses of the ocean, may be shown to be incorrect by a consideration of the character of the sedimentary rocks of the land on the one hand, and of that of the deposits of the sea-floor on the other. The sedimentary rocks, even in the most massive palæozoic formations where they attain depths of several miles, are shallow-water deposits, formed out of the waste of the land and always laid down near land. Nowhere among them, even including the thick organically-derived limestones, such as the chalk, is there any formation which properly deserves to be considered that of a deep sea. Recent researches into the nature of the sea-bottom across the great ocean-basins have likewise shown that the deposits there in progress have no real analogy among the rocks of the land. The conclusion to be drawn from the evidence is that the great ocean-basins faave always existed, and that the terrestrial areas have also lain on the whole over those tracts where they still exist.
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Geographical Evolution 1 . Nature 19, 490 (1879). https://doi.org/10.1038/019490a0
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DOI: https://doi.org/10.1038/019490a0