of Victorian Auriferous Occurrences. 33 



galena and stibnite is described by Ub-ich as forming a casing in 

 a flaiiii on the Eagleliawk Reef, Maldon (1) It assayed 17 per 

 cent, cnppri- and 45oz. gold per ton. On occount of the marked 

 ditterence in the gold contents and the mode of occurrence I 

 place this sepfunte from the Thompson River ore. It approaches 

 most nearly some of the dolomite veins which occur in the first 

 group, but differs in the prominence of chalcopyrite. 



6. Pyrrliotite chalcopyrite. — The association of these two 

 minerals with one another is well-known in some important 

 copper-mining localities. In Victoria they often occur in the 

 quartz reefs, but I find no example of their occurrence in important 

 quantity apart from other groups. They appear together as an 

 addition to the grou[is. At Bethanga the addition of these two 

 minerals to the minerals of the first group produces an ore in 

 which coppei' is present in important quantity (6). At IMaldon 

 the two minerals are recorded by Moon more often from the same 

 mine than separately (10). At Mt. William, in the Grampians, 

 as described below, they (tccur with the minerals of the next 

 group, but the comparison with mineralogically similar occur- 

 rences in the Gong Gong granite near Ballarat indicates that they 

 may be regarded as independent. At the Gong Gong reservoir 

 small quantities of pyrrliotite and chalcopyrite occur in the 

 granite of a small quarry, and molylxlenite is found in the same 

 granite a mile away. 



Evidence is wanting as to their influence on gold contents of 

 the ore. At Cobar, N.8.W., these minerals with pyritc form 

 the ore worked for copper and carry a little gold, but at a rate which 

 would be worthless wheie these minerals only themselves form a 

 small quantity of the ore. 



The localities of these minerals togethei' are mostly near 

 granitic rocks, or where the rocks are somewhat altered. Pyrrlio- 

 tite occurs at Piggoreet ; hei'e also the rcjcks are more schistose 

 than usual in the bedrock of the Ballarat district, but the altera- 

 tion cannot be due to the nearest granite area on the surface, as 

 it is too far away. It seems more likely to bean outcrop of older 

 rocks than usual. 



Pyrrhotite occurs at Castlemaine and at Newstead. These 

 also may be not far from granitic rocks. 



