72 AUSTRALIAN QUATERNARY CLIMATES AND MIGRATION 



tially a jungle-people and in no sense a food-raising people. 

 How far habitable conditions for such existed on the so-called 

 savannah south of the fringe of the tropical rain-forest is proble- 

 matical. If we could determine it with certainty, we might say 

 with more precision when they appeared on the Australian main- 

 land. The northern half of the savannah to which these habitable 







MILES 

 100 500 



Rainfall-reliability Belt 



FIG. 13. 



Climatic Belts and Rain-reliability Belt when the Tropical rain-forest reached 



Cape York. 



conditions were seemingly confined, reached the Cape York 

 Peninsula about 21,000 years ago. An estimate based on these 

 considerations is that the Australoids came between 15,000 and 

 18,000 years ago, at a time when the savannah was habitable and 

 before it showed signs of the approaching aridity. That the 

 Australoid could acclimatize himself to arid conditions is evident 

 from his subsequent history; that he did not at first choose an 

 arid environment is obvious. 



When Torres Strait was formed, he was completely cut off 



