Page:Popular Science Monthly Volume 41.djvu/843

From Wikisource
Jump to navigation Jump to search
This page has been validated.

persistence of the chief outlines of the continents seems to be opposed to the admission. Dr. Ihering, who has devoted a good deal of time to the study of the fauna of South America, boldly concludes from his own special researches that during the Secondary period a great continent extended from Chili and Patagonia, through New Zealand, to Australia, while the connection between South America and North America was broken during both the Cretaceous period and a great part of the Tertiary epoch. The striking differences between the faunas of both Americas, and the identity of many representatives of the faunas of South America and South Africa, make him also conclude that the two latter continents were connected as late as the Oligocene period.[1] R. Lydekker, whose opinion has such a weight in the matter, also concludes from the many known affinities between the fossil faunas and floras of the four great southern prolongations of the continental mass of the globe that they must have stood in a more or less intimate connection, and have been partially isolated from the more northern lands,[2] As to F. Ameghino, he also recognizes that, at least during the Oligocene times, South America was in direct connection with the Old World; but he points out the similarity of the mammalian and Dinosaurian faunas of both Americas, and concludes that the two continents must have been connected, as well as North America with Europe, at an earlier epoch.

It would be premature to attempt now the solution of this complicated question. It may be permitted, however, to point out that the hypothesis of a submerged antarctic continent is not improbable from the point of view of the physical geographer. The permanence of the continents, which is a fact, and seems to be opposed to the hypothesis, must be understood in a limited sense. In the equatorial and the two temperate zones we undoubtedly have huge continental masses, the great plateaus of Asia, both Americas, and Africa, which, so far as our knowledge goes, have not been submerged since the primary epoch; and around these backbones of the continents we have huge masses of land which have not been under the sea since the end of the Secondary period. But their outskirts have witnessed several retreats and invasions of the ocean, or of its Secondary period seas. Moreover, the permanence of the continents does not seem to extend to the circumpolar zones. When we consider the outlines of the two great plateaus of East Asia and North America, we see that these two great continents of the Secondary epoch

  1. Revista Argentina de Ciencia Natural, No. 4 (Sobre la distributión geográfica de los Creodontes, and letter to F. Ameghino).
  2. Nature, 1892, vol. xlvi, p. 12.