346 REPORTS OF RESEARCH COMMITTEES. 



found in the Upper Tertiary leads O'Ccurring on the high table- 

 lands with a now relatively cold cliinate. This former mild 

 climate was accompanied by a lower elevation of the land, the 

 highest ridges of which did not in all probability exceed 1,000 

 feet. He mentions also the associatioin O'f giant marsupials with 

 this vegetation, and suggests that they coiuld not have existed 

 had not the forest beeii of a rich sub-tropical type; they would 

 have certainly died under preseint conditions. This author also 

 quotes E. C. Andrews with reference to the waste-clogged valleys 

 or the Tertiary rivers of the New South Wales area, and sug- 

 gests that at various stages in the era. the climate was, perhaps, 

 more moist and denudation more active, but he notes that changes 

 in elevation of the land might account quite well for the filling 

 and scouring out of these waste-filled valleys. 



During the Pleistocene period the climate became much colder, 

 probably about 5 deg. C. colder than at present, and, as this was 

 accompanied by uplift of the land, the arid conditions increased 

 cr the western plains of the State, and they experienced a climate 

 analogous to that which obtained on the eastern side of the South 

 Island of New Zealand during the glacier extension and succeed- 

 ing it. This arid condition of New South Wales is probably con- 

 temporary with that recorded by Mr. Chapman from the Mallee 

 bores in Victoria. 



Dr. H. I. Jensen has kindly furnished the follcwing valuable 

 note en North Australian Quaternary Climate : — 



The Northern Territory. 



" That there has been a Pleistocene arid cliinate in the Northern 

 TerritoTy is evident from the great extent oi laterites and por- 

 cellanites which cap heterogeneous geological formations. The 

 Northern Territory was a peneplain with very disintegrated 

 drainage and undergoing arid erosion. During the arid cycle 

 the decomposing surface strata were indurated toi porcellanite in 

 the case of sandstone and to' laterite rock where the formations 

 carried ferro-magnesian minerals. 



Where there is a capping of porcellanitic sandstone, 50 feet or 

 so in thickness, broken by a fault, the sandstone is usually capped 

 with white porcellanite and the fault with laterite. Hence, 

 around Darwin you get what seem large dykes of laterite in po^r- 

 cellanite. On diorite and granite the surface detritus and in- 

 durated decoimposed rock have the characters of laterite. 



We have recent sandstones with crayfish remains. Pleistocene ( ?) 

 beds with crocodile bones and teeth, Ctetaceo-tertiary beds with 

 ammonites and belemnites, all changed superficially into laterite 

 and porcellanite. So, also, we get Permo-carboniferous ( 1) and 

 Cambrian sandstones which have suffered the same superficial 

 change. 



