582 THE GEOLOGY OF THE WARRUMBUNGLE MOUNTAINS, 



disappear altogether. In the Pilliga Scrub it is generally useless 

 to sink for water in or near a creek bed. 



(5) Many of the wells and bores sunk in the district, at alti- 

 tudes of between 1,000 and 1,500 feet, strike water which rises 

 to a constant level, and gives a good pumping supply but does 

 not overflow. This is the case at the Goorianaw^a bore and at 

 many wells near Bugaldi. 



The lower the altitude at which the well is sunk, the deeper 

 one has to dig for water, and the higher it rises in the well. 



These wells which maintain a constant level are evidently 

 sunk in artesian or subartesian strata near the intake. 



At still lower altitudes artesian water has been obtained by 

 sinking deeper, and it overflows at the surface, as at the Kalga 

 Bore and Tenandra Bore. 



(6) In places on Bugaldi Creek a trickle of water has been 

 obtained a few feet down. On sinking deeper, into soft sand- 

 stones, all the water has been absorbed, and no new supply has 

 been obtained. 



From 'these considerations we may deduce the following 

 conclusions : — 



(1) The Warrumbungle streams are supplied by mountain 

 springs. 



(2) The Artesian Intake Beds of the Triassic system outcrop 

 at a level of from 1,500 to 1,000 feet to the north-west and west 

 of the Warrumbungles. Hence streams disappear at this le^'el, 

 a feature which is partly brought about by the aridity of the 

 plains. 



(3) Bores in the intake beds give a permanent pumping supply 

 but no overflow. 



(4) A well in Triassic Sandstone may give a permanent pump- 

 ing supply if cut through a pervious stratum into an underlying 

 impervious one. On deepening it, one may cut into a second and 

 lower pervious layer, and the well will dr}^ up again. 



(5) East, north-east, and south-east of the Warrumbungles, the 

 formations are Permo-Carboniferous and Lower Trias, therefore 



