PROBLEM OF THE GREAT AUSTRALIAN ARTESIAN BASIN. 145 



Except for the two gaps through which the Northern 

 and Central railways have been run, the watershed seems 

 to attain an altitude of from 2,000 to 2,500 feet, quite 

 sufficient to account for the pressures met with in the bores 

 out to the west. 



South-eastwards from Roma, the Jurassics form a broad 

 belt curving past Dalby and Toowoomba to the New South 

 Wales border, where they rest upon palaeozoic rocks, etc., 

 and have a considerable development east of Moree, extend- 

 ing from Narrabri to Dubbo, where their outcrop comes to 

 an end. 



Pittman's recognition of Tceniopteris Daintreei 1 in cer- 

 tain wells and in the Moree, Ooonamble, Nyngan, Wallon 

 and Bulyeroi bores, indicates the presence of the Jurassics 

 beneath the Cretaceous cover over a large region, con- 

 siderably extended by a similar discovery at Salisbury 

 Downs far to the west (north of Wilcannia). Excepting 

 by David, 2 there seems to be a reluctance on the part of 

 geologists to admit that these fresh- water beds have any 

 great sub-Cretaceous extension in Queensland, and that 

 they form the real Artesian Series there. Yet quite a 

 number of bores in this State derive their water from a 

 series of sandstones and shales with coal-seams underlying 

 the marine blue shales, not only along the eastern margin 

 (Muttaburra-Blackall-Roma), but well out within the 

 basin, e.g„ Kynuna and the deep bores at Elderslie and 

 Bimerah, and at Canobie well to the north of Oloncurry. 



Whether these beds actually extend across to the west 

 and south-west, is an important question upon which very 



1 Mr. Pittman's announcement was made in 1895. Annual Report 

 Department of Mines, New South Wales, p. 123. In 1891 Mr. Robert 

 Etheridge identified Tceniopteris in strata pierced by the Nyngan (sub- 

 sequently proved) sub-artesian bore. Annual Report, Department of 

 Mines for 1891, p. 320.— Eds. 



2 Federal Handbook, B.A.A.S., p. 280. 



J— July 4, 1917. 



