PROBLEM OF THE GREAT AUSTRALIAN ARTESIAN BASIN. 199 



of granite were brought up by the bailer. Flowing water 

 was obtained near the bottom of this deep crack, but the 

 supply was much smaller than in the surrounding bores, 

 but with a greater static head. 



There was no evidence to show that sandstone filled the 

 crack, and therefore, despite Pittman's attempt at ex- 

 planation on these lines, Gregory's view seems far more 

 reasonable. Unless such fissures be highly numerous, the 

 probability of one being struck in the course of random 

 boring would be excessively low. 



The Urisino "tidal well" in New South Wales instanced 

 by Gregory in support of his views, is hardly a suitable 

 subject in this respect, on account of the obscurity of the 

 phenomenon; the investigation of the behaviour of certain 

 4t oscillating" bores near Oradock 1 in the Cape Province, 

 has shown some of the difficulties inherent in elucidating 

 the causes of such movements of water-level. 



Taking into consideration the irregularities of tempera- 

 ture, pressure and salinity, as pointed out under those 

 separate heads, each of which is admittedly small but 

 collectively of appreciable weight, the composition of the 

 waters and their associated gases, the contentions stated 

 above appear to be justified, and agree with David's 2 dictum 

 that springs connected with faults obviously supply part of 

 the artesian water. At the same time waters of a similar 

 type, either plutonic or resurgent, could have entered the 

 broad outcrop of the Jurassic beds beneath the covering 

 of basalts and thus assisted in the charging of the reservoir. 



XI. The Closing History of the Basin. 

 Elaborating this conception, the additions both along the 

 eastern outcrop and from below are suggested as having 



1 A. Young, Trans. Eoy. Soc. S. Africa, Vol. in, p. 61, 1913. 



8 T. W. E. David, Handbook for Australia, B.A.A.S., p. 280, 1914. 



