133 



evidence of a subterposed impervious bed, added to wbicb is tbe 

 fact of tbe general uniformity of level at wbicb tbe water is 

 met witb. Tbe flow seems to be directed in a somewbat south- 

 easterly direction, and if so, doubtlessly contributes to the 

 largely known volume of water wbicb emerges to tbe surface in 

 tbe low-level swamps in tbe Soutb-east. Tbe underground 

 flow by way of Mount Gambier to MacDonnell Bay must be 

 from an independent source — without doubt derived from per- 

 colation of surface waters. Tbe summer water-level of the 

 Eiver Murray at Morgan has been determined by tbe officers 

 of tbe Eailway engineering staff to be two feet only above low- 

 water mark at Port Adelaide, and that of the highest flood 38 

 feet ; whilst tbe level of tbe subterranean water beneath 

 Mount G-ambier is about 90 feet above ordinary low-water 

 mark at MacDonnell Bay. 



I have already suggested (Trans. Eoy. Soc. S. Aust., vol. ii., 

 p. 1.) " the probability of obtaining supplies of water on the 

 artesian principal over some portions at least of the Mesozoic 

 Plains, and possibly over those portions covered by the ' Desert 

 Sandstone,' in the interior part of this continent." I was led 

 to express that opinion from the fact of the mode of occurrence 

 of, and from certain peculiarities exhibited by, the " mound 

 springs," which occur around the west and south shores of 

 Lake Eyre. The water of the springs flows to the surface of 

 an open level plain in an arid climate, and possesses a high 

 temperature and a not inconsiderable amount of saline matter, 

 tbe chief of which are calcium salts ; whilst the geographical 

 distribution of tbe springs coincides with tbe outcrop of tbe 

 Jurassic rocks, at least so far as is known. The constancy and 

 volume of the flow point to sources of supply more copious and 

 regular than that which could be furnished by the rainfall on 

 tbe Peake Eanges, which bound tbe Jurassic Plain on tbe west, 

 or that gathered on the hill country to the southward, or even 

 from both sources ; and the high temperature of the water 

 W'Ould indicate a more distant origin. If, therefore, we could 

 ascertain the direction of the underground flow, what an in- 

 estimable boon will be proved to be within our reach — a means 

 at our command to bridge over tbe sterile wastes which render 

 unavailable pastoral tracts beyond. As to the whereabouts of 

 tbe source of these artesian waters, I can point to none other 

 than tbe tropical rains wbicb fall on the divide separating the 

 Albert and Korman Elvers on the north from the Barcoo on 

 the south. Hence, tbe direction of flow is roughly from the 

 north-east to the south-west. Let, therefore, a steady advance 

 be made by borings from the known artesian-well region in a 

 north-east line, feeling one's way, as it were, by the sti-ati- 

 graphical sequence wbicb shall first have been ascertained by 



