CRETACEOUS ROCKS OE NEW SOUTH WALES. 
345 
The examination recently made by me convinces me that the 
Paleozoic areas shown on our Geological Map must be considerably 
reduced, and that, on the other hand, the area occupied by the Cretaceous 
or water-bearing rocks is much larger than was previously supposed. 
Perhaps the most important conclusion at which I have arrived is 
that the artesian basin has probably a much further extension south - 
wards than had been previously assigned to it. It has been hitherto 
considered that the southern boundary of the Cretaceous basin was 
formed by a bar or buried range of Palaeozoic rocks stretching west- 
wards from Cobar through Wilcannia to Scrope’s Range. At 
Wilcanuia the rocks forming this bar were regarded as Devonian , and 
this opinion appears to have been formed on lithological evidence 
only, as there is no record of any Devonian fossils having been found 
in situ , nor of any geological section in which the relation of these 
Wilcannia sandstones is described with regard to older sediments. 
But in my opinion the lithological character of these sandstones points 
to their being of Mesozoic rather than of Palaeozoic age, and the small 
amount of geological evidence that can be obtained from a surface 
examination seems to strengthen that view. Deposits of hard sedi- 
ments which I observed at certain localities, such as at the west of 
the Koko Range, at Eooningberry, at the western side of Mount 
Murchison, at the western side of Wovchugga Lake, at the Springs, 
and at the northern end of Scrope’s Range, may be, and probably are, 
of Devonian age. They consist of hard, dense, thick-bedded quartzites, 
similar in character to those of Mount Lambie, near Bathurst, show- 
ing slickensided joints, and, as a rule, lying at a high angle with the 
horizon. But the rocks at Wilcannia are of a different character ; 
they consist of rather soft, yellowish, greyish, and whitish grits and 
sandstones, frequently containing bands and pockets of kaolin, and 
lying as a rule at a very low angle of inclination. In fact, while one 
set of rocks shows abundant evidence of both metamorphism and 
disturbance, the other is remarkably free from signs of either. My 
conclusion in regard to these rocks is that they are probably of Upper 
Cretaceous age, and if this be correct it means that, instead of the 
Cretaceous basin being cut off on the south by an east and west 
boundary through Wilcannia, there may be a deep channel somewhere 
between Woychugga Lake and Mouut Manara, by which the artesian 
basin may extend far to the southwards — possibly even under the 
Eocene beds of the Lower Darling, the north-western portion of 
Victoria, and part of South Australia to near Mount Grambier, where 
fresh water has, I believe, long been known to escape from the beach. 
In the neighbourhood of Port Macdonell, near the S.E. extremity of 
South Australia, several strong springs of fresh water have been 
described as coming up from below the level of low water, and 
discolouring the ocean for some distance around. These subterranean 
rivers are thus referred to by the Rev. J. E. Tenison Woods in his 
book, “ Geological Observations in South Australia,” pp. 363 and 
364 : — “ Close to Mr. Ellis’ station, within about five miles of Mount 
G-ambier, there is a whim erected over a small hole in the rocks. 
Underneath this, at the depth of about 70 feet, there is a long passage 
or cavern through which a deep stream of water flows. It has been 
