of the earth in its adjustment to the new ellipsoid of rotation. But it is a mistake to believe that only a difference of degree exists between such alterations of level and the submergence of a continent to the deep sea floor. For the last case would involve the changing-over of the upper frequency maximum of the earth’s crust to the lower, and we should be in need of a physical cause for the favouring of the level of the ocean floor and the absence of the intermediate layers; which is not forthcoming (see Chapter III). The partisans of the permanence doctrine have thus at their disposal good arguments against the doctrine of the submerged bridging-continents.
But since they start from the obvious assumption that the continents have always lain where they do to-day, the advocates of the permanence theory arrive at false conclusions from their accurate premises when they explain: “The great ocean basins are permanent features of the earth’s surface, and they have existed, where they are now, with moderate changes of outline, since the waters first gathered.”[1] When we bring into consideration horizontal drift movements of the continents, we can only uphold this principle so far as to agree that the total areas of the continental blocks and of the ocean floors, except for the compression of the former in the course of time,
- ↑ Bailey Willis, “Principles of Palæogeography,” Science, 31, N.S., No. 790, pp. 241–260, 1910. This is certainly a very blunt statement. Other authors, as, for example, Sorgel (“Die Atlantische ‘Spalte,’ Kritische Bemerkungen zu A. Wegener’s Theorie von der Kontinentalverschiebung,” Monatsber. d. deutsch. Geol. Ges., 68, pp. 200–239, 1916), seek a via media, in which they would allow the bridging-continents to shrink up as much as possible to narrow bridges on the margin of the ocean basins. But this compromise is not a very happy one, since on one hand the explanation of the affinities is rendered more difficult, and on the other the requirements of physics are only insufficiently fulfilled.
