of Victorian Aiirifero'iis Occurrences. 29 



widespread feature where tlie favoural)]e bed is most resti'icted, 

 and the access of the solutions, by a crack nearly at right angles 

 to the indicator, is at the same time facilitated and most defini- 

 tely localised. Slipping on the carbonaceous bed might then 

 conti-ibute by rendering more easy the percolation of solutions 

 along the beds, providing thus a more ready supply of the active 

 ingredient of these impermeable beds. 



Extensions and moditications of the first type. At places in a 

 reef there sometimes appear small quantities of additional 

 minerals. Thus from the Albion Reef, 8teiglitz, Ulrich i-ecords 

 (2) stibnite, tetrahedrite, and bournonite, with pyrite, sphalerite, 

 gold and pholerite in the hollows of the quartz. The tetrahedrite 

 contains arsenic, iron and zinc. From the Band and Albion 

 Mine, Ballarat, Ki'ause records (5) calcite, dolomite, siderite 

 with pyrite, chalcopyrite and tetrahedrite. Boulangerite and 

 bournonite have also been recorded from Ballarat, but all these 

 are rare. 



Chalcopyrite occurs at a nuiuber of localities, according to Mr. 

 R. H. Walcott, more especially Eastern Victorian (4). Mr. H. 

 S. Whitelaw (9) describes the best reefs at Berringa as containing 

 galena and chalcopyrite. It appears to be much commoner there 

 than at Ballarat. Mr. O. A. L. Whitelaw (16), states that the 

 minerals accompanying the lodes at Wood's Point are mainly 

 pyrite and galena, with smaller quantities of sphalerite, copper 

 carbonates and jamesonite. Mr. D. Clark (6) states that in the 

 Cassilis ore, where the sulphides form from 10 to 60 per cent, of 

 the ore, arsenopyrite is most prominent with pyrite, sphalerite, 

 galena, chalcopyrite and small quantities of stibnite and bismu- 

 thinite. Magnesium and aluminium silicates are present in this 

 ore. At the Maude and Homeward Bound Mine, Mount Wills, 

 pyrite and arsenopyrite are accompanied by a little stibnite and 

 a silver sulphantimonite. 



The Bethanga ore contains the ordinary minerals of the tii'st 

 type of occurrence with the addition of those mentioned below as 

 group 6, chalcopyrite and pyrrhotite, in quantities exceeding the 

 sphalerite and galena (6). The Maldon field gives many 

 examples of the addition of the same two minerals, according to 

 the report of Mr. R. A. Moon (10), with the addition of a variety 



