PROBLEMS OF THE ARTESIAN WATER SUPPLY OF AUSTRALIA. 119 



proved that this rock contains an appreciable proportion 



of alkalies. The results were as follow : — 



Sample from near Dubbo, N.S. Wales ... j g°^ sh J|r< 



Sample from near Texas on the Queensland- j Potash 2'06f 

 New South Wales Boundary I Soda 0*45f 



The two localities are about 300 miles apart. 



The soda and potash in the artesian water are thus easily 

 accounted for, while the rain which falls upon the catch- 

 ment area doubtless contains the usual proportion of 

 carbonic acid, and an additional source would be provided 

 by the oxidation of organic matter. 



Lithium Carbonate.— With regard to the alleged presence 

 of lithium carbonate in the Helidon wells it may be observed 

 that these wells are outside the artesian basin, as the 

 sketch-section (Plate VIII.) will show, and therefore the 

 occurrence in them of lithium or any other substance would 

 have no significance so far as the subject under discussion 

 is concerned. As a matter of fact, however, Mr. Henderson 

 the Queensland Government Analyst, informs me that he 

 has examined three samples of Helidon water for lithium 

 and has failed to find a trace of it even with the aid of the 

 spectroscope. 



Zinc in Toowoomba Water?— The reputed presence of 2-J 

 grains of zinc per gallon in "the well of Toowoomba " can 

 also be shown to be a matter of no consequence, so far as 

 the origin of the artesian water is concerned. The town 

 of Toowoomba is built, at an altitude of about 2,000 feet, 

 upon a flow of basalt which forms the surface of the well 

 known Darling Downs. The basalt overlies the Triassic 

 sandstones, which dip to the westward, and which here 

 constitute the intake beds of the artesian basin. The basalt 

 is very vesicular in character, and is found to contain a 

 plentiful supply of water, which is doubtless derived from 

 rainfall. As a consequence of this a great number of wells 



