31:8 REPORTS OF RESEARCH COMMITTEES. 



The drainage of the Territory has, through the elevatory move- 

 aient, which has now extended to all parts except the Cape Wilber- 

 force corner, completely changed. The Daly, the Victoria, the 

 Roper, which were miner streams, have been re-juvenated and 

 are now the chief rivers. The lower portion of the McArthnr, 

 fiom Mc Arthur Station to the sea, is alsoi a new river. The old 

 stream flowed north-east into the gulf near the mouth of the 

 Limmen. An east-west gorge has since been cut through 10 miles 

 of sandstone 400 feet high. 



These changes in the course of the streams were probably 

 Pleistocene. The Barkly tablelands afford no evidence of the age 

 of their elevation. It was probably Tertiary. The patches of 

 marl with late Tertiary lacustrine shells found in places on the 

 Barkly tablelands do, however, ]>oant to" a late period- of disin- 

 tegrated drainage which presumablv antedated uplift. It has 

 beein an area of continued arid conditions, but the formations 

 were unfavorable to the developinent of laterites. 



North Queensland. 



Laterites, and in some places, porcellanites, cap great areas" in 

 Cape York Peninsula and in other parts of north and central 

 Queensland. 



Laterite cappings occur in places on the Jurassic sandstone 

 tableland west of Cooktown, alsoi on the Newcastle Range between 

 the Einasleigh and Etheridge Rivers, and also around Charters 

 Towers. The formation of these tableland laterites immediately 

 preceded the uplift of the tablelands, and pro'bably were de- 

 veloped in Early Pleistocene times. Uplift, followed by increased 

 rainfall, brought about the dissection of the plateaux. 



North Queensland in Mesozoic and Early Tertiary times pro- 

 bably extended far into' the Pacific. Great areas have been lost 

 by faulting and Tertiary subsidences. In Jurassic times most of 

 North Queensland was shallow sea. Sedimentation ccntinued dur- 

 the marine Cretaceous, but the area was uplifted into the late 

 Cretaceous and continuous land then extended across the present 

 Gulf of Carpentaria. The Gulf was foimed by depression in. the 

 late Tertiary periods or in the Pleistocene after the Jura-Cretaceou.s 

 rocks had been worn down almost to a peneplain. 



The Gulf of Carpentaria as a whole is very shallow and is 

 full of shifting sandbanks. These are partly derived from sands 

 borne down by rivers in flood, but one is tempted to think that 

 much of the sand was formed by arid erosion prior to the de- 

 pression of the Gulf. Mesas of Permo-carboniferous sandstone, 

 like the Pellew Islands, Mai'ia Island, and Groote Island, rise out 



