Page:The origin of continents and oceans - Wegener, tr. Skerl - 1924.djvu/103

Rh Jurassic up to the Eocene. Moreover, it is to be noticed that the very numerous faunal affinities of Australia to South America, which obviously used Antarctica as a bridge, but which up to now have not been found there, are not considered by Arldt, and his table on the whole is naturally not drawn up in the form most suitable for our purpose.

Both the remaining separations in our table give bridges near areas in which the blocks are still to-day connected, namely, the Central American bridge and that across the Bering Straits. Bridges of this sort naturally play no rôle in the displacement theory, since the previous ideas of a temporary emergence and re-submergence by shallow seas are not changed. The two bridges are really only mentioned as examples to remove certain misunderstandings. The study of maps shows that the present connection of the blocks between South and Central America does not at all depend on accidental contact. These blocks have rather been attached to each other from the most ancient periods, even if they have been temporarily submerged, as indicated in our table. Apparently the connection was above water in the Silurian and Devonian, again in the Permian to Middle Trias, still again in the Cretaceous, and—this is uncontested—after the Miocene. The continuous connection of the blocks is in no way contradictory to the fact that South America detached itself from Africa before North America did from Europe, particularly if the great plastic deformations which Central America must have undergone are borne in mind. The movement of South