100 THE ROYAL SOCIETY OF CANADA 



Such veins are composed largely of quartz, and in them, besides 

 gold, the following Tellurides have been recorded. 

 Calaverite 

 Hessite 

 Sylvanite 

 Tetradymite 

 Altaite 



Associated with the quartz gangue the following minerals have 

 also been recorded. 



Calcite 

 Ankerite 

 Sericite 

 Chlorite 

 Tourmaline 

 Scheelite 

 Galena 

 Zinc blende 

 Tetrahedite 

 Molybdenite 

 Pyrite 



Arsenopyrite 

 Chalcopyrite 

 • Bornite 

 Covellite 



Where the enclosing rock is schistose the veins usually run more or 

 less closely parallel to the schistosity, or at a comparatively low angle 

 to it. Where their general strike varies from that of the schistosity 

 of the rock they usually follow the lines of the schist for certain dis- 

 tances and then cut suddenly across it, in this way forming step-like 

 veins, both in vertical and lateral extention. Where the transverse 

 breaks are small the whole vein system may appear as a series of 

 disconnected lenses arranged en echelon. The mineral bearing solutions 

 rose through the rock along the lines of least resistance, sometimes on 

 fault planes, but more usually on planes where crushing or shearing 

 forces, possibly assisted by shrinking, had caused lines of weakness 

 and incipient fracturing. As the solutions rose through the rock they 

 deposited quartz with the minerals associated with it. From these main 

 channels the solutions spread out into the adjoining rock, altering it, 

 and replacing portions of it with quartz and pyrite, so that most 

 of the veins as now seen are portions of the rock itself which have 



