188 ON THE GEOLOGY AND PETROGRAPHY OF BATHURST, N.S.W., 



I have often noticed fibrous green malachite as pseuclornorphs 

 after azurite at the Cobar copper mines. Grey copper ore is 

 recorded, on good authority, as occurring in the Cow Flat copper 

 mines. These mines are now closed. 



29. Gold. — Gold is found in the drifts of the Macquarie, and, 

 more or less abundantly in the shingle beds forming river terraces 

 back to the pliocene " leads." The fact that gold is found in 

 water courses cutting through decomposed granite rocks, such as 

 in those creeks on the common near Bathurst, is thought by some 

 to prove that the gold has been shed from a granitic matrix. While 

 admitting that, in some instances, gold may be derived from a 

 granitic rock,* yet, in our case, it is unnecessary to fall back on 

 any such supposition. I venture to account for the presence of 

 the alluvial gold in this way. The Bald Hills are some 600 feet 

 above the Bathurst Plains. On their summits there rests a 

 layer of basalts covering pliocene drift. This drift has been 

 proved by tunnelling to carry gold. At some points the basalt 

 and underlying drift have been entirely removed by denudations, 

 while along their whole length the margins of the drift have been 

 eroded. The detrital matter, with its auriferous deposit thus 

 obtained, has been spread out between the hills and the river, 

 during all that period that the river has been cutting its way from 

 its old position to its present level. The gold now obtainable in 

 the granite creeks is, in fact, a re-distributed pliocene lead. The 

 character of the gold confirms this theory. It is not possible to 

 distinguish the gold washed from the creeks from some flakes 

 found in the highest drifts. In the creeks referred to the precious 

 metal was never found in quantities sufficient to pay for its 

 recovery. 



30. Diamonds. — Although I have not seen a diamond from any 

 of the drifts round Bathurst, it may be well to refer to the fact 



* For an interesting article on gold in granite, see Clarke's " Southern 

 Gold-fields : Researches in the Southern Gold-fields of New South Wales, 

 by the Rev. W. B. Clarke, M.A., F.G.S. ;" Sydney, Reading & Wellbank, 

 1860. 



