158 ALEX. L. DU TOIT. 



rock at nearly similar depths, and furnish an approximately 

 similar yield: — Tycannah (Govt.) (-7°), and Tycannah 

 (Priv.) ( + 2°); Bunna Bunna(-7°), and Bulyeroi ( + 5°); 

 Midkin No. 3 (-8°) and Talmoi ( + 8°), differences amount- 

 ing to 9°, 12° and 16° respectively — the last remarkable 

 indeed ! 



To the west of Bourke the bores Wanaaring, Cuttaburra, 

 and Kelly's Oamp, have increased 8°, 9° and 10° respectively, 

 while the deep Elderslie No. 2 bore in Queensland has risen 

 from 202° to 211° F. Symmonds has noted considerable 

 fluctuations in the temperatures of the bores at Neargo and 

 Dolgelly in New South Wales. 



A fall of temperature could easily be brought about by 

 reduction in pressure, whereby water from a higher and 

 cooler stratum would be allowed to enter. The slotting of 

 the casing above the main horizon, so usual in the Ooo- 

 namble district, will therefore explain the general drop in 

 that region. 



Neither the regular movement of water from regions of 

 greater depth and therefore of higher temperature will 

 serve to explain the departure noted in the Moree district, 

 since, instead of neighbouring bores being affected in the 

 same manner, the changes are frequently of opposite sign, 

 and this is so, irrespective of whether the bores are down 

 to bed-rock or not. 



Though difficult of interpretation according to the 

 meteoric hypothesis, such thermal abnormalities can readily 

 be explained as having arisen through the contributing of 

 of juvenile waters to the reservoir, an action that would 

 be furthered by reduction of the static head of the bores 

 concerned. 



On this point further investigations are greatly to be 

 desired. 



