64 AUSTRALIAN QUATERNARY CLIMATES AND MIGRATION 



V. Palaeogeography of the Postglacial and Last 

 Glacial Periods. 



The Proto-Inclics or Australoids by whatever routes they came 

 to Australia had to pass over some deep channels and no eustatic 

 lowering of sea-level in the last 50,000 years has been nearly suf- 

 ficient to expose the floors of them. During the Postglacial, the 

 last glacial stage (Wurm 3) and the antecedent interglacial, 

 there has not been a landbridge connecting Australia with Asia 

 or with the islands to the north except New Guinea. One existed 

 at some earlier geological period long before the earliest 

 evidence obtained by the writer of the presence of man in Aus- 

 tralia. That the Proto-Indics in their migration southwards had 

 recourse to sea-travel, was realized by Elliot Smith (1930) who 

 pointed out that they had to cross Wallace's Line between Borneo 

 and Celebes. In these notes on the palaeogeography of the regions 

 north of Australia, it will be seen that they had to pass over much 

 wider extents of water. The distribution of land and sea during 

 the Postglacial and at the close of the last glacial periods are 

 discussed together with the climatic changes that are known to 

 have occurred during those stages — changes that had a profound 

 bearing on habitation and migration. 



During the last glacial stage, Daly (1934) estimates a lowering 

 of sea-level of about 294 feet. The northern strand line of Aus- 

 tralia and the south-west strandline of New Guinea were then 

 continuous; New Guinea was joined to Australia by a more or 

 less extensive coastal plain (Pig. 10). This extended in places 

 more than 150 miles north of the existing coastline of Australia, 

 and on the south-western side of New Guinea some 350 miles, 

 including what are now the Aru Islands ; it extended as far east 

 as Long. 145° which passes through the Gulf of Papua, east of 

 Cape York. At its northern extremity, it was nearest Suli 

 Mangoli, the easternmost of the Sula Islands of the Celebes 

 Group, and in the west to Timor. 



There are peoples in Sumatra, Borneo, and Celebes with a 

 Proto-Indic background. These three islands were joinel during 

 the 294 feet lowering of sea level except at the Strait of Macassar 

 (Fig. 10) which, at its narrowest, was about 30 miles wide. To 

 migrate to a region further south, the route, even if it were partly 

 by land, was also necessarily by sea, requiring the use of some 

 kind of sea-travel. There are certain probable routes leading to 

 the point opposite and nearest to Australia, the shortest distance 

 across the deep channels, routes that brought would-be migrants 

 with their primitive means of transport within possible crossing- 

 distance. These are the Celebes — New Guinea route, the Timor 



