REPORTS OF RESEARCH COMMITTEES. 349 



of the Gulf, and east of Cape Gray the Gulf is studded with 

 granite tors. The sandstone of Wellesley and Mornington Is- 

 lands is supposed to be Jurassic. All are capped on the summits 

 with laterite. 



The distribution of Diprotodon remains through central and 

 south-west Queensland points to a wet period antedating the 

 present. The Hann Expedition in 1872 found remains of extinct 

 vertebrates on the Walsh River. Diprotodon is recorded from 

 Clermont, the Condamine, the Darling Downs generally, the 

 Burdekin region, and many places far west. 



Another piece of evidence of the drying up of the northei'n 

 climate is the capture of the Gulf river systems by the coastal 

 rivers flowing into the Pacific. Thus, the Barron River is captur- 

 ing the headwaters of the Walsh River. The depression of the 

 east coast of Queensland may, of coiurse, be helping the prccess. 



All the geological evidence points strongly toi the climatic 

 changes in the Tertiary having been of the character indicated 

 by Dr. Taylor, and tO' North Australia having gradually become 

 wetter in recent times. The increased wetness is not due to the 

 slightly greater elevation to-day, for there has been no mountain 

 building in these parts since the Carboniferous, and the elevation 

 of the Cretaceous peneplain has been so slow that the cov;ntry has 

 been kept pretty low-lying throughout by erosion." 



This opinion is supported by Talbot and Clarke, as a result of 

 their examination of that part of Western Australia which borders 

 South Australia (Geol. Survey Bulletin No. 75, 1917, pp. 67 and 

 69). Their conclusion is based on the form of the land surface. 



Western Australia. 



The question of change of climates in Western Australia has 

 been discussed by Jutscn in Bulletin No. 61, Geol. Survey of 

 Western Australia, 1914. Basing his conclusions on a considera- 

 tion of the circumstances of deposit of the ' ' deep leads ' ' O'f the 

 Salt Lakes and Central Divisions of that State, he expresses an 

 opinion that some of these do certainly indicate a change from a 

 moister to a more arid climate within coinparatively recent geo- 

 logical times; though, on the other hand, the formation of others 

 of these "deep leads " may be explained without having recourse 

 to this hypothesis. Those included in the former category are 

 considered to be deposits in old valleys formerly ercded deeper 

 into the surface during a moister period and then filled by aggrad- 

 ing streams incompetent to carry their load as the climate became 

 drier. As the increased rainfall may be explained either by- 

 greater elevation of the land or by closer proximity of the sea 

 owing to its transgression over the area considerably beyond the 

 present coastline, this hypothesis does not necessarily involve any 

 secular change in climate, though there are decided evidences for 



