Hedley apparently considers that the migrations referred to above took place in an interglacial period, but the Patagonian beds in which the fossil marsupials are found are Tertiary and not Quaternary. No direct evidence of an interglacial period has been found in Antarctica, nor, considering the intensity of the glaciation which the country is even now undergoing, is any such to be expected, and we can only infer from the bipartition of the Glacial period in Australia, New Zealand and South America—which, in New Zealand at least, was associated with submergence—that there was probably a similar bipartition in Antarctica. Nordenskjold states that the submarine relief showing river erosion which, in Tierra del Fuego, was developed partly at least in the interglacial period, is also developed in West Antarctica. It is improbable that the ice ever entirely vanished from the continent. We shall see in Chapter XIV that even the comparatively brief warm period known as the post-glacial climatic optimum extended to the Antarctic coast, and this is additional argument for extending the much greater interglacial oscillation southward beyond its known limits in Tierra del Fuego, Australia and New Zealand, but here the matter must be left. BIBLIOGRAPHY Hedley, C. “The palæographical relations of Antarctica.” _London, Proc. Linnæan Soc._, 124, 1911-2, p. 80. Lydekker, R. “A geographical history of mammals.” Cambridge University Press, 1896, pp. 125 ff. David, T. W. E. “Antarctica and some of its problems.” London, _Geogr. J._ 43, 1914, pp. 605-30. Nordenskjold, O. “Antarktis.” _Handbuch Regional Geologie_, Heft 15, 1913. CHAPTER XIII THE CLOSE OF THE ICE AGE—THE CONTINENTAL PHASE In Chapter V we left the climatic history of northern Europe at the point where the ice in its final readvance had once more reached the German coast. But Scandinavia was now sinking, and the margin of the ice soon began to retreat again. At the same time the Alpine glaciers diminished in size, while the Irish and Scottish glaciers disappeared. This is the critical period in the change from glacial to temperate conditions, and, thanks to the researches of the Swedish geologists, and especially G. de Geer, H. Munthe and Gunnar Andersson, we are very well acquainted with it. The change was not uniform; at first the recession was very slow, and there were periods when for scores of years the ice-edge remained stationary or even readvanced, but on the whole the time was one of persistent amelioration. The following description is based chiefly on W. B. Wright’s summary of de Geer’s work.