the Antarctic continent had its great extension northward can perhaps hardly be definitely decided upon at present. Hutton argues for the Jurassic period as the period of greater extension; but since he wrote much further evidence has arisen, and it seems probable that the date should be placed later—perhaps in Eocene times. Ortmann, discussing the matter from a somewhat different aspect, considers that it probably occurred in the Cretaceous and Eocene periods" (Dr. C. Chilton, in Subantarctic Islands of New Zealand, vol. ii, p. 807: Philosophical Institute of Canterbury, 1909). But even if Antarctica was united at later times to Australia or to the southern extremities of South America and South Africa at the time the western and more ancient part of Australia possessed "the ancestral forms of its strange marsupial fauna, both of which it had probably received at some earlier epoch by a temporary union with the Asiatic continent over what is now the Java Sea" (Island Life, by Alfred Russel Wallace, p. 497), we could only conceive of marsupial forms occurring on the continent of Antarctica. It is quite clear from the fossils brought home by Dr. Donald of the Scottish Expedition of 1892–93, by the more recent able researches of Dr. Otto Nordenskjold and his companions during the Swedish Antarctic Expedition of 1901–04 in the same
