David, T. W. E. “Australasie. Les conditions du climat aux époques géologiques.” Rep. Congr. Geol. Internat., 10, 1906, pp. 275-98.
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Gagel, C. “Beiträge zur Geologie von Kaiser-Wilhelms Land.” Beitr. geol. Erforsch. deutsch. Schutzgebieten, Berlin, 1913, H. 4.
Marshall, P. “The glaciation of New Zealand.” Trans. New Zealand Inst., 42, 1909, p. 334.
Salenka, M. L. et al. “Die Pithecanthropusschichten auf Java.” Geol. und Palæol. Ergebnisse der Trinilexpedition (1907 und 1908). Leipzig, 1911.
CHAPTER XII
THE GLACIATION OF ANTARCTICA
The great Antarctic continent offers a unique problem to the glacial climatologist, for here we have a land area with the theoretical snow-line already at sea-level, and accordingly covered with a thick ice-sheet that leaves only a few mountain ranges and nunataks exposed above its surface, and yet in the past these ice-sheets and glaciers have attained a thickness several thousand feet greater, and have extended further north. Various suggestions have been made to account for this former extension, perhaps the most remarkable being that it coincided with a milder and therefore snowier climate. This, however, is untenable, for the Glacial period of Graham Land and the South Orkneys is obviously a southward extension of the Glacial period of Tierra del Fuego, which was obviously due to a colder climate, and can be traced northward along the Andes into tropical regions. A more fruitful suggestion is that as one of the most potent factors in preventing the accumulation of snow is at present the wind, it was a decrease in the strength of the wind which enabled the ice to reach a greater thickness. This is probably true in a sense, the decrease of wind force being due to a great increase in the area of the Antarctic continent during the Quaternary.
We have seen that in the early Quaternary there was great elevation in the south of South America and also in Australia and New Zealand. The amount of this elevation increased southward and was very great near the polar circle. This is borne out by considerations based on the distribution of living and fossil animals, which point very definitely to a land connexion between Australia and South America in Tertiary and early Quaternary times, most probably by way of Antarctica.
The first line of evidence is the distribution of the marsupials, living and extinct. As is well known the chief home of this type of mammal is now in Australia and New Guinea, but in Tertiary deposits in Patagonia remains of extinct forms known as Dasyurids have been found, which are allied to Australian forms, and can only have come from Australia, probably via Tasmania. Secondly, there are two peculiar families of fresh-water fishes, the Haplochitonidæ and Galaxiidæ, the first common to Australia and South America, while one species of the second is found in New Zealand, Tasmania, the Falkland Islands and Patagonia. Thirdly, Beddard has found an intimate relation between the earthworms of New Zealand, Eastern Australia and Patagonia. Finally there is a curious similarity between the slugs of Patagonia and those of Polynesia.