502 



THE ORE-DEPOSITS OF BORAH CREEK, 



From this it would appear, that the main Conrad Lode and the 

 large fault which intersects it, are younger than the Elsmore- 

 Tiiigha system of fractures; for it is difficult to imagine how such 

 a large and permanent fissure could have escaped alteration 

 during the epoch of formation of cassiterite veins. The fault 

 referred to is, in the main, due to horizontal strain. The fault- 



Text-fig. 3. — Illustrating the relation of the 

 lodes to the geology of the district. 



T.G., Tingha Granite— A. G., Acid Granite— 

 B., Basalt— S., Slate. 



plane is nearly vertical, hading slightly to the west; and the 

 horizontal displacement of the lode, which is itself practically 

 vertical, amounts to about 15 feet. It is probable that the 

 fissure was formed to relieve the strain due to the final^^stages in 

 the cooling of the granite-stock. 



