207 



miles, we have 7,000 square miles of water-bearing beds to draw 

 from. 



To render tlie waters stored up in the Menindie basin available 

 for the Broken Hill mines, there are no insuperable difficulties, 

 and the cost need not exceed some .£100,000. 



The fine drift-sand of the upper water-bearing stratum has 

 proved the cause of serious loss and a very large expenditure. 

 It was found impossible to maintain a sufficiently deep hole to 

 receive the well-buckets, and the attempt to do so usually ended 

 in the well collapsing sooner or later. The pumping-engines now 

 employed have, on the whole, answered very well, but to reach 

 the best and the deepest water, it is only necessary to use iron 

 caissons, double lined, as used in the erection of bridges where 

 mud and soil must be penetrated before reaching a sound founda- 

 tion. 



Before fixing the actual site for the well, a preliminary survey 

 of the natural features would be advisable to select the best pipe- 

 track and sites for the positions of a few bores towards the centre 

 of the basin ; the bores will determine the most favourable strata 

 for well-sinking, which could be done very quickly, as no stone or 

 rock is to be passed through. A six-inch bore would be advisable, 

 as the cores are certain to render valuable geological information. 

 1 should like to see a really competent consulting geologist 

 engaged to report upon them, as it would add much to our 

 scanty knowledge of the circumstances under which these wide- 

 spread beds were deposited, and their relation to the period of 

 deposition of the Murray Cliffs. 



Now, as to the objection which has been raised as to the 

 probability of the supply proving inadequate. AjDart from the 

 uppermost beds, where the water is slightly brackish, several 

 others were jjassed through before reaching the gravelly 

 beds, which contain the best water ; and in the only bore 

 which reached them, namely, that from bottom of the Silistria 

 Well, the hydrostatic pressure was so great that the pebbles 

 were shot up through the bore to the bottom of the well, 

 n distance of 130 ft. This unmistakal)ly proves the existence of 

 a very large body of water, and, added to this evidence, we have 

 to consider the very large area over which these Newer Tertiary 

 beds extend, the thickness of the various water-bearing strata, as 

 well as the supply obtained from Kars and Middle Camp Wells 

 {although both these wells are only sunk a little distance 

 into the first of these strata) ; all of which circumstances 

 demonstrate the practically inexhaustible character of these 

 underground waters, and more than corroborate Mr. C. S. 

 Wilkinson's views, expressed in a private letter to me 

 some time after this paper was fii'st written, but before 



