116 E. F. PITTMAN. 



grade has a fairly uniform fall to the west and north-west. 

 It may be added that the discrepancies noticed in the 

 pressures of the adjacent wells may be due to their deriv- 

 ing their water from different porous beds. In connection 

 with this question Mr. Allan ] writes : — 



"It must however be remembered that whilst in the case of 

 Government bores the records have been well kept and the different 

 flows determined until bed-rock has been obtained, yet in the case 

 of private bores such data are not available, and there is the 

 consequent possibility of the recorded pressure in a private bore 

 being for a flow in a much higher sheet of water-bearing strata 

 than that noted in connection with an adjacent bore. This neces- 

 sitates the isopotential lines being taken as tentative." 



Salinity of Artesian Waters.— Amongst Professor J. W. 

 Gregory's objections to the theory of hydrostatic pressure, 

 as applied to the Australian artesian basin, some of those 

 upon which he lays most stress are based upon the chemical 

 composition of the water. He states (1) that the water 

 does not increase in salinity with sufficient regularity as it 

 flows from east to west, or in other words from its source 

 to the most distant wells; (2) that the dissolved constituents 

 vary irregularly in nature as well as in amount in the wells 

 of the central basin ; (3) that the presence of the carbonates 

 of soda and potash in the majority of the well waters, of 

 lithium carbonate in the Helidon wells, and of zinc in "the 

 well of Toowoomba " are evidence in favour of theplutonic 

 origin of the water. 



With regard to objections (1) and (2) it is surprising that 

 any geologist should expect that a stratified deposit could 

 extend for a distance of 600 miles, or more, without show- 

 ing marked variations in what may be termed its accidental 

 constituents, or that the salinity of water which percolates 

 through it for that distance should increase regularly, from 



1 Ibid., p. 45. 



