PROBLEM OF THE GREAT AUSTRALIAN ARTESIAN BASIN. 139 



reason of the incompleteness of the returns and the abridge- 

 ment of details as regards strata cut, number of water- 

 beds, their thickness, their yield, temperatures of the 

 various flows, pressures, etc.; still it is believed that on 

 the whole the graphic presentations are not far from the 

 truth, except where the bores are scanty and far apart. 



The excellent bibliography given by Pittman, makes it 

 unnecessary to attach a list of the important papers on the 

 problem; the reports of the Interstate Conferences are 

 referred to as I and II for convenience. 



II. The Physiography of the Basin. 



While valuable accounts have been written by Jack, 

 David, Pittman, Cameron and others, there has curiously 

 enough been no comprehensive and detailed description of 

 the entire basin, attention having naturally been concen- 

 trated more upon the problem of the origin of the water, 

 and unfortunately, it is precisely in regard to certain 

 important and even vital points that data are particularly 

 lacking. 



One of these is concerned with the nature of the sub- 

 surface contour of the great hollow, about 1,200 miles long 

 and 700 or 800 wide, filled in with Mesozoic beds, resting 

 upon a compact basement of Palaeozoic and older sediments, 

 granites and other igneous rocks. For the New South 

 Wales portion, a good idea can be obtained by plotting from 

 the records of such bores as are known to have bottomed 

 on bed-rock (II. App. B.), assisted in places by those that 

 have failed to reach the very base of the artesian beds. In 

 Queensland, it is only occasionally that bores have struck 

 the underlying foundation, an exception being the tract 

 Y-shaped in plan, stretching northwards from Tooleybuck 

 across the Northern Railway to Savannah Downs and to 

 Canobie ; the bores in this section are all shallow. There 

 are also a few cases in the south between Cunnamulla and 



