PROBLEMS OF THE ARTESIAN WATER SUPPLY OF AUSTRALIA. 101 



IV. An inclination of these beds, so that the edge at 

 which the waters enter will be higher than the surface 

 of the well. 



V. A suitable exposure of the edge of the porous stratum, 



so that it may take in a sufficient supply of water. 



VI. An adequate rainfall to furnish this supply. 



VII. An absence of any escape for the water at a lower 

 level than the surface of the well. 



With regard to condition III, it may be observed that 

 the Artesian basin of Perth, Western Australia, is believed 

 to have no continuous impermeable covering, nevertheless 

 the water rises well above the surface in bores. Attention 

 was drawn to this fact by the writer in 1901, and it was 

 suggested that where even porous sand rocks form the 

 upper strata of a basin, they offer such resistance to the 

 vertical ascent of the water that if a bore be put down to 

 the water-bearing bed a flowing well may result from the 

 sudden relieving of the pressure. 1 



In 1905 Mr. M. L. Fuller, an eminent American geologist 

 also described the occurrence of Artesian water at Long 

 Island, New York, in some gravel and sand beds which 

 have no impervious covering. He stated that, according 

 to Mr. A. C. Veatch, "the occurrence of flows depended 

 upon slight differences in the degree of porosity of the 

 sands, which, however, were in all cases pervious through- 

 out." 2 



It appears, therefore, that an impermeable covering is 

 not an absolutely necessary condition for an Artesian basin, 

 although it is present in most large basins. 



1 The Mineral Resources of New South Wales (E. F. Pittman) 1901, p. 

 458. 



2 Contributions to the Hydrology of Eastern United States, 1905, M. L. 

 Fuller, U. S. G-eol. Sur., Water Supply and Irrigation Paper, No. 145, 

 pp. 40-41. 



