I.—Subsidence and Elevation, and on the Permanence of Oceans

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The theory of permanent Continents and Oceanic basins, opposed as it is to the general teaching of text-books, seems to have given rise to comparatively little discussion. In the latest edition, for instance, of Lyell's Principles, we read: “It is not too much to say that every spot which is now dry land has been sea at some former period, and every part of the space now covered by the deepest ocean has been land.” The new theory has been upheld chiefly by Sir Wyville Thomson, Prof. Geikie and Mr. Wallace. The latter especially has collected every kind of evidence together that seems to support it in his latest, and most admirable work, “Island Life.” By a process of reasoning, supported by a large array of facts of different kinds, he arrives at the conclusion that the distribution of life upon the land, as we now see it, has been accomplished without the aid of important changes in the relative positions of continents and seas. Yet if we accept his views, we must believe that Asia and Africa, Madagascar and Africa, New Zealand and Australia, Europe and America, have been united at some period not remote geologically, and that seas to the depth of 1000 fathoms have been bridged over; but we must treat as “utterly gratuitous, and entirely opposed to all the evidences at our command,” the supposition that temperate Europe and temperate America, Australia and South America, have ever been connected, except by way of the Arctic or Antarctic Circles, and that—lands now separated by seas of more than 1000 fathoms depth have ever been united.