180 



taining with certainty how the acids and bases are combined in 

 the original water : — 



Parts per 100-000. 



317-407 



This takes no account of organic matter, Avhich is present in 

 sufficient quantity to blacken the residue on ignition. 



The Stratigraphical Relations of the Ter- 

 tiary«formations about adelaide, with 



ESPECIAL REFERENCE TO THE CrOYDON- 

 BORE. 



By Professor Ralph Tate, RG.S., F.L.S., &c. 



Plate lY. 



[Read October 9, 1890]. 



Not many weeks since a bore was commenced at Croydon, 

 three and a-half miles from Adelaide; but at the present date 

 operations have been suspended, w'hen a depth of 800 feet w^as 

 reached. Whether the boring will be resumed is not yet de- 

 cided on ; but it is earnestly hoped, in the interest of geologic 

 science, and to the attainment of the fullest knowledge of the 

 water-bearing capabilities of the formations underlying the Ade- 

 laide-plain, that the bore will be extended into the Archaean 

 rocks, Avhich is necessary to ensure a certain measure of finality 

 as regards the scientific as well as the utilitarian aspect of the 

 exploration. 



The geological information hereby gained is supplementary to 

 the foregoing communication on the Dry Creek-bore ; and because 

 of this it is deemed undesirable to postpone the publication of 



