PROBLEMS OF THE ARTESIAN WATER SUPPLY OF AUSTRALIA. 139 



known to occur in the State of New South Wales, where 

 the artesian water most certainly occurs in the older 

 Triassic (or Trias-Jura) sandstones. 



The Trias-Jura rocks of Queensland are characterised by 

 the presence of the fossil plants Tceniopteris Daintreei and 

 Thinnfeldia, and these fossils have also been recognised in 

 New South Wales, both in the great artesian basin and in 

 the Clarence River basin. In the Hawkesbury (Triassic) 

 Sandstones of New South Wales, which are lithologically 

 indistinguishable from the last named, Tceniopteris Dain- 

 treei has not, so far, been met with, although Thinnfeldia 

 is plentiful. It is not quite certain therefore, at present, 

 whether the Hawkesbury Sandstones of New South Wales 

 are identical with the Trias-Jura Sandstones of Queensland, 

 or whether they occupy a lower geological horizon than 

 the latter. About 20 miles north of Gulgong (New South 

 Wales) there is a fresh water (lacustrine) deposit contain- 

 ing numerous fish remains together with Tceniopteris 

 Daintreei and other plants. 1 This deposit occupies a 

 denuded hollow in the Hawkesbury Sandstone, and it has 

 been pronounced by Dr. A. S. Woodward, on the evidence 

 of the fish, to be of Jurassic Age. It is of course possible 

 that this deposit may be the equivalent in age of the 

 water-bearing rocks of the artesian basin, in which case 

 the latter would be newer than Triassic. 



1 The Fossil Fishes of the Talbragar ■ Beds. Memoirs Geol. Sur. N. S. 

 Wales, Palaeontology No. 9, 1895. 



