WATER SUPPLY 
235 
Queensland Parliament passed a Bill to prevent waste of 
this water; but it was rejected by the Upper House on 
the ground that the waste was immaterial. This simple 
explanation of these wells is inadequate. The sandstones 
are often too compact to transmit water readily ; the catch- 
ment, especially in the northern area, is insufficient as the 
available intake there, the Blythesdale Braystone, outcrops 
only in a region of limited rainfall and high evaporation, 
and is not crossed by any rivers which could discharge large 
supplies of water into the sandstone. As has been pointed 
out by Dr. du Toit it would take centuries for water from 
the supposed intake to reach the western wells. Moreover, 
many of the water-bearing sandstones are thin lenticular 
layers which are not likely to be of great extent, and their 
water cannot be renewed from the supposed intake. The 
author suggested in 19oI that the well is largely connate 
water, which had been stored in the beds since their formation, 
and is partly plutonic water, which contributes the high 
gas-pressure that forces the mixed water to the surface 
(cf. Dead Heart of Australia, 1906, pp. 271-341 ; Geog. Fourn., 
xxxviil, I9I1, pp. 34-59, 157-81). Numerous hot springs 
occur to the E. of the basin, and if others discharge under 
the Rolling Down Formation the water would accumulate 
in any porous beds or joints at a high temperature. Owing 
to this plutonic water in parts of the country the well water 
in places rises above the calculated hydraulic surface; thus 
at Coomburra, N.E. of Burke, where the water would be 
raised by water-pressure to only 800 feet, the actual pressure 
is sufficient to uplift it to 1058 feet. Various groups of 
wells have also (Proc. Pan-Pac. Sci. Congr., 1923, ii, pp. 1294-5) 
an abnormally high temperature. These Australian well 
waters are unusual by their poverty in sodium chloride and 
sulphates, by being highly alkaline, and by many containing 
boric acid, which is regarded as indicative of plutonic origin 
unless it has been dissolved from secondary borates. The 
chemical composition of these waters is fully consistent with 
their plutonic origin. In recent years the wells have fallen 
in yield throughout practically the whole area, the average 
decrease in all the bores in New South Wales from 1903 to 
1908 being 5% per cent. per annum, and in the wells gauged 
periodically from 1914 to 1921, the annual decrease was