of Victorian Auriferous Occurreoices. 31 



centrated sample of ai'senopyrite from it, 20oz. to the ton. The 

 gold, if not in the arsenopyrite, was at least associated with it. 



Mr. H. S. Whitelaw regards chalcopyrite and galena as con- 

 stantly present in good gold-bearing stone at Berringa (9). 



The alteration by surface waters of the minerals of these reefs 

 gives rise to marcasite (which, however, is easily decomposed), 

 melanterite from marcasite, copiapite ; limonite ; orpinient and 

 realgar very rarely ; scotodite probably much more often than 

 I'ecorded, pharmacosiderite, kaolin, pholerite, epsomite, and other 

 minerals. 



2. At St. Arnaud, Percydale, and other localities in the 

 Pyrenees there is a great prominence of galena and sphalerite. 

 Accompanying this there is, as might be expected, a larger pro- 

 portion of silver in the output of the mines. Some parts of the 

 ore yield concentrates which have been smelted for lead. The 

 difference from the preceding type is the great quantity of these 

 minerals which in the ordinary association of minerals are quite 

 subordinate. In some samples of these ores the proportion of 

 quartz also is comparatively small. The general result of assays 

 at Percydale is said to have been that a large amount of galena 

 tended to give high silver contents, and a large amount of sphal- 

 erite good gold contents in the ore. An assay at the Ballarat 

 School of Mines of a sample from St. Arnaud containing galena, 

 sphalerite, pyrite and arsenopyrite, with little quartz, gave : 

 silver 19oz. 12dwt., gold 2oz. 19dwt. llgr. per ton. From the 

 Glendhu Reef, Landsborough, an assay of pyrite is quoted by 

 Ulrich (1) as giving: silver 42oz. 9dwt. 14gr., gold loz. 4d\vt. 

 llgr. The material is quoted as an example of pyrite rich in 

 silver. It is not unlikely that it was originally associated with 

 galena, and, if so, may be regarded as analogous to an instance 

 from the Pinnacles, Barrier Ranges, given by Jaquet (11), where 

 a mixture of galena and pyrrhotite had 75 per cent, of its silver 

 in the pyrrhotite, though that mineral without galena was poor 

 or bai'ren. 



The galena at Buchan, East Gippsland, where it is found 

 nearly free from sphalerite, seems to contain very little gold. A 

 sample of concentrates from the Buchan Proprietary Mine gave 

 55 per cent, lead, silver 21oz., gold 3dwt. per ton (12). A quartz 



