PRESIDENTIAL ADDRESS. 55 



west warp became developed, while in Bathurst-Monaro, 

 and New England, northerly to north north-easterly trends 

 crossed the older north north-westerly trends. The Queens- 

 land Divide was at this time probably very close to the 

 Queensland east coast line. 



In Trias-Jura time great lakes isolated the New England 

 area from the southern end of the old Main Divide near 

 Brisbane, and a prolonged subsidence set in over the region 

 between Brisbane and Lake Eyre, and to the south of the 

 rising Main Divide of Victoria, which had now tilted back- 

 wards the glacial beds of Permo-Oarboniferous age towards 

 the old, now destroyed Divide far south. (See Fig. 6 b.) 

 The Wannon-Otway-Gippsland sediments were laid down 

 in a trough trending east and west, the southern portion 

 extending far up into the V of Tasmania. 



In Cretaceous time a great sagging continued of the 

 region between Lake Eyre and Roma, as well as on a 

 meridional direction from midway between these points 

 and the Gulf of Carpentaria. The epicontinental sea of the 

 Cretaceous transgression may have completely severed 

 eastern Australia from western from the Gulf of Carpen- 

 taria, via Lake Eyre, to the head of the great Australian 

 Bight. In Tasmania the further sagging of the old Trias 

 Jura Basin was accompanied by the extrusion on its southern 

 margin of immense sheets of quartz-dolerite. The Cretace- 

 ous transgression also submerged a little of the northern 

 part of Northern Territory and an extensive but narrow 

 strip along the west coast of West Australia. 



In Cainozoic time warping ceased at the northern and 

 central portions of what is now the largest artesian basin 

 in the world, the Cretaceous Basin, from the Gulf of Car- 

 pentaria towards Lake Eyre. Further south downward 

 warping submerged much of the southern portion of Vic- 

 toria, the north-west coast of Tasmania, the south coast 



