136 ALEX. L. DU TOIT. 



I. Introduction. 

 By reason of its colossal size and extraordinarily economic 

 importance, the Great Artesian Basin of Australia eclipses 

 all others, and the interest therein is heightened by the 

 exceptionally fascinating nature of the problems of its 

 structure and mechanism. 



For many years the obvious view that the basin owed its 

 immense supply entirely to rainfall absorbed on its eastern 

 and south-eastern margin, remained almost unquestioned, 

 and it was not really until in 1906 Prof. Gregory 1 showed 

 that many of the facts were irreconcilable with such a 

 simple scheme, and that the meteoric theory was seriously 

 challenged. 



He concluded that a certain part at least of the water 

 was of magmatic origin, some was probably ivater included 

 in the sediments during their deposition, or was a subse- 

 quent though ancient accumulation from the atmosphere, 

 and only the remainder was being drawn from the present 

 rainfall, or that of very recent times, while in 1911 2 he 

 went so far as to deny even the importance of the last- 

 named action. 



In 1912, Mr. Symmonds, 3 adducing many reasons backed 

 up by chemical data and going even further than Gregory, 

 concluded that the bulk of the water was "juvenile" or of 

 plutonic origin. 



Against such views Mr. Pittman, 4 until lately Govern- 

 ment Geologist of N. S. Wales, the most uncompromising 

 protagonist of the meteoric theory, vigorously protested, 



1 J. W. Gregory, The Dead Heart of Australia, London, 1906. 



2 J. W. Gregory, The Flowing Wells of Central Australia, Journ. 

 Eoy. Geogr. Soc., Vol. xxxvin, 1911. 



3 R. S. Symmonds, Our Artesian Waters, Sydney, 1912. 



* E. F. Pittman, Geol. Surv. N. S. Wales, especially, Problems of the 

 Artesian Water Supply, etc., 1908; The Great Australian Artesian Basin, 

 1914; The Composition and Porosity of the Intake Beds, etc., 1915. 



