136 



Often a vein may show a width of ten feet but the 

 fractured portion may be only a few feet, or even inches, 

 wide along either wall. In this portion there may be many 

 streaks of dark mineral which are often parallel, giving- a 

 banded character to the ore, as in many of the veins in the 

 north part of Whitney and Tisdale, namely, at the 

 Mullholland, Scottish Ontario, Davidson and adjoining 

 properties. A similar banded structure is seen at the Rea 

 mine. At these properties tourmaline is the principal 

 mineral of the streaks. The gold may occur along these 

 lines or in the intervening quartz, which is often much 

 crushed and filled with later minerals. 



Several sections were examined, which showed grains 

 of gold apparently enclosed in the primary quartz, but the 

 occurrence is much less prominent than where gold occurs 

 in the crushed areas. 



It is important to note that practically all the veins which 

 are gold-bearing contain considerable carbonate of varied 

 composition. Wherever the enclosing rocks are schistose 

 they always carry carbonate and frequently effervesce with 

 cold hydrochloric acid. Much of the carbonate of the veins 

 has been absorbed from the wall rock, while portions have 

 been formed from ascending solutions which circulated 

 through the veins. Pyrite and grains of gold frequently 

 occur in the carbonate. 



Carbonate in the form of ankerite constitutes the main 

 portion of veins at the West Dome, Apex, and in parts of 

 Deloro township. This carbonate is distinctly earlier than 

 the quartz veinlets which intersect the ankerite veins. Both 

 the ankerite and quartz have been fractured and veinlets of 

 later carbonate deposited in them. 



Since the whole surface of the area has been deeply 

 eroded and glaciated, there is now little evidence of 

 secondary enrichment. The enrichment is very super- 

 ficial, extending only from a few inches to a few feet 

 in depth. The outcrops of the veins and wall rocks are 

 usually discolored or decomposed, due to the oxidation of 

 the iron pyrites and the ferrous carbonate in the ankerite or 

 other iron-bearing carbonates. Cubes of iron pyrites are 

 occasionally obtained at the surface, while copper pyrites 

 and arsenopyrite also occur near the surface. Where the 

 veins have been oxidized to any depth, there are generally 



