PALEOGEOGEAPHY OF ANTAECTICA HEDLEY. 447 



Actually the revei*sc is the case. South America is the most closely 

 associated with Tasmania, then New Zealand is less so, and the mid- 

 Pacific islands not at all. 



Those who consider the demand for land between Tasmania and 

 Antarctica as exorbitant are not consistent in asking so much larger a 

 grant in the Pacific. 



Another difficulty is why that South American contingent which 

 flooded Tertiary Antarctica, and then Australia, failed to include such 

 characteristic South American fauna as the humming bu'ds, platyiiiine 

 monkey's, hystricomorph rodents, edentates, or notoungulates. Dr. 

 von Jliering explains (Trans. N. Z. Inst, vol. 24, 1891, p. 431, and N. 

 Jalii-b. f . Mineralogie, etc., Beil.-Bd., vol. 32, 1911, p. 176, pi. v) that 

 two former subcontinents of late Mesozoic or early Tertiary age are 

 now fused in tlie present South America. Before the rise of the 

 Andes these were separated from each other by a broad sea and main- 

 tained distinct fauna and flora. The southern tract, which he calls 

 "AiThiplata," comprised what is now Chile, Argentina, and southern 

 Brazil. The northern area, called '' Archiguyana," embraced northern 

 Brazil, Venezuela, and Guiana. 



It was from Archiplata that the last phase of Antarctica had its 

 American derivatives, and that at a time when many forms now 

 regarded as typically South American had not yet reached Archiplata. 

 Not until after Antarctica was released from Archiplata did the latter 

 join Archiguyana, and then the southern fauna suffered tlie usual fate 

 from the incursion of the more highly organized northern types. 



3. THE AUSTRAL FAUNA AND FLOKA. 



More space than is here available would be required to enumerate 

 the Antarctic refugees in austral lands. A few of the more strikmg 

 instances are now selected. 



Recent marsupials are restricted to Australasia and to the Americas, 

 the monotremes to the former. It seems to have been assumed gen- 

 erally that marsupials necessarily had a European origin and traveled 

 across Siberia to North America. A shorter connection between 

 western Europe and South America by way of Archhelenis is at any 

 rate worth debate. Had the entry to Australia been by the Malay 

 xVrchipclago, as opponents of the Antarctic hypothesis advance, then 

 stragglers by the way should have lingered in the East Indies. In 

 Australasia marsupials and monotremes are least developed in the 

 north; proceeding southward, more groups successively a))pear, till 

 ultimately Tasmania has, as Prof. Spencer expressed it, ''a condensa- 

 tion of most that is noteworthy in the AustraHan region." (Spencer, 

 Proc. Austr. Assoc. Adv. Sci. 1892, p. 106.) Indeed, the most con- 

 vincing proof of the Antarctic theory is the fact that in Australasia the 

 South American affinities regularly increase as Tasmania is approached 



