AUSTRALIAN QUATERNARY CLIMATES AND MIGRATION 73 



from communication by land with other races. It is probable 

 that during the 7,000 years between his first appearance and his 

 isolation, there were at least three waves of migrants. 



Those who used the western route either came by the littoral as 

 migrants from the east or as immigrants by some kind of craft. 

 Although the shortest distance from Timor to the mainland was 

 the most likely route taken, other routes were possible. As con- 

 tiguous sides of the strait separating Timor from the mainland 

 were both in the tropical rain-belt for the first time in the Post- 

 glacial period 11,000 years ago, it seems likely that immigration 

 by this route started then. There are no records of Proto-Indics 

 east of Java in the Sumatra-Timor chain of islands ; this is peopled 

 by Malays and Melanesians. It may be found that the Proto- 

 Indics were there 11,000 years ago, but their suspected absence 

 makes the spread of the tropical rain-forest to Timor and the 

 mainland less significant. 



The following tabulation gives the years previous to the present 

 time when geographical, climatic, and environmental conditions 

 existed. 



Years. Geographical, climatic and environmental conditions. 



2,000 End of period of extreme aridity. 



4,000 Postglacial Optimum. Arid belt reaches southernmost limit. 



6,000 Beginning of period of extreme aridity in southern Australia. 



8,000 End of pluvial period in southern Australia. Torres Strait formed; 

 Australia isolated from New Guinea. 



11.000 Rain-forest reached both sides of Timor Strait. 



15,000 Tropical rain-forest reached Cape York Peninsula. 



16,000 Mid-Postglacial coastal plain. 



18,000 Probable first appearance of Australoids in Australia. 



24,000 Beginning of submergence of the glacial coastal plain. 



As stated {supra p. 70), these figures tire based on the radiation 

 curve and a maximum estimate for Wurm 3, but if Steck's mini- 

 mum estimate for this be taken at 9,000 years, the appearance 

 of the Australoids in Australia in its present form was less than 

 6,500 years ago, and the other figures correspondingly less. 



VIII. Migration Routes in Australia 

 As Cape York Peninsula as part of the old land-bridge that 

 joined New Guinea to Australia was the first and main place of 

 entry for the Proto-Indics, the degree of habitability in the past 

 of the tracts leading from it suggests the favoured routes for 

 migration on the mainland. The availability of food and water 

 was the assurance that intending migrants sought, and this was 

 regulated by the movements of the climatic belts and with them 

 the rainfall-reliability belt. As pointed out, the latter moved 

 furthermost north in the glacial period and widened to its maxi- 



