PROBLEM OF THE GREAT AUSTRALIAN ARTESIAN BASIN. 179 



and the curves smoothed off, but, if so, it should be em- 

 phasised that it is of the highest importance that every 

 apparent discrepancy be fully investigated before being 

 rejected, because one of the very few direct indications of 

 the irruption of magmatic waters below the Basin, will be 

 afforded by the presence at each such point of an area of 

 higher potential entirely surrounded by a region of lower. 



There are several high potential areas, the isolation of 

 each of which appears sufficiently well defined, while there 

 are a number also where the bores are not sufficiently close 

 together to make it certain that the region of higher 

 potential is not merely a lobe. 



Sixthly, owing to the rapid fall of pressure that the bores 

 are showing, there will always be discrepancies between the 

 static pressures got, solely by reason of the different dates 

 upon which such measurements had been made. 



The Map attached has been compiled almost entirely from 

 the records in the Report for 1912, and does not therefore 

 profess to give much more than the general direction of the 

 isopotentiat curves for about that year; it might be com- 

 pared with that in the Report of the Hydraulic Engineer, 

 Queensland for 1900, (App. Map A, No. 9). 



Like the latter, it proves the existence of the two regions 

 of exceptionally high potential, the first immediately to the 

 east of Hughenden, and the second to the north-east of 

 Charleville, the hydraulic surface just exceeding 1,450 feet 

 on the Burenda Lease; it throws out a prolongation or lobe 

 as far westwards as Thargomindah at least. 



From Richmond there is a depression of the hydraulic 

 surface towards the north-west and the potential falls right 

 across almost to OLoncurry, where there is a small local 

 area of high potential, just south of Oorindi railway sta- 

 tion; this is rather a curious feature, but whether it arises 



