“Sa 
E. F. PITTMAN AND T, W. E. DAVID. CxXI. 
South Wales occasionally attain a height above the sur- 
rounding plains of 500 feet, and a maximum altitude of 
about 900 feet above the sea, as at Mount Poole in the 
Grey Ranges. The higher hills frequently exhibit steep 
escarpments, the beds being horizontal or nearly so, and 
having vertical joints.' The beds consist of conglomerates, 
sandstones, and porcellanites anda very fine grained white 
siliceous rock having much the appearance of kaolin in 
general character. Occasionally the sandstones and por- 
cellanites are very ferruginous, and it is thought that these 
beds have contributed largely to the material of which the 
red soils are formed. The porcellanized portions are 
impervious to water, but some of the sandstones are very 
porous, and it is conceivable that, as pointed out by Dr. 
Jack, where they overlie the intake beds they may act as 
feeders to the artesian supply. 
Rolling Downs Formation.—As already stated, this 
formation, though proved by the artesian bores to have an 
extensive development in New South Wales, does not out- 
crop at the surface with the exception perhaps of the 
marly clays, already mentioned, seen in the north bank of 
the Darling at the bridge above Bourke. At about 20 
miles west of Depot Glen near Mount Poole, the spoil heaps 
of some shallow wells show marine fossils of Lower Cre- 
taceous age, proving that that formation comes very close 
to the surface at this point. 
Owing to the fact that most of the artesian bores in 
New South Wales are made with percussion drills, the 
material penetrated is so ground up that it is very difficult 
to decide at what depth the Cretaceous beds and the Trias 
pespectively begin. In two notable cases, however, viz., 
1 A description of this formation has already been given by one of the 
authors.—The Mineral Resources of N.S. Wales, by Edward F. Pittman. 
pp. 464 — 465. 
