﻿296 Canadian Record of Science. 



biotite granite containing a good deal of plagioclase. The 

 quartz and feldspar show marked indications of great 

 pressure. Much biotite, partially altered to chlorite is 

 present and is associated with epidote, perhaps also an 

 alteration product, having, however, in one case a core of 

 allanite. 



Tliis specimen was considerably decomposed, being from 

 near a vein and also near the surface. Two other 

 specimens, one of them from a granite horse in a quartz 

 vein, and the other from a cross-cut tunnel several miles 

 distant, showed much the same characteristics, especially 

 in the evidence of great crushing. The hand specimens 

 do not show this crushing to any great extent, though the 

 feldspar crystals are not very regular in outline at times. 

 In this granite, which by the way, differs a good deal from 

 the intrusive granites which break through the Slocan 

 Slate series, near Three Forks, to the north, there are 

 several distinct classes of mineral-bearing veins. These 

 classes of veins differ both in origin and in the nature 

 of the material filling them, but all occur in this typical 

 porphyritic granite. 



Class I. The most common and the most characteristic 

 consists of irregular veins of coarsely crystallized opaque 

 quartz. They vary quite rapidly in width, both laterally 

 and in depth ; their usual width is under four feet ; their 

 dip is very low, being from 10° to 50° from the horizon. 

 Xo one of these veins has yet been explored to a greater 

 dei)th than 100 feet. Hence all observations are con- 

 fined to little more than surface showings. 



Where shafts have been sunk a good deal of displacement 

 is revealed along slickensided planes, more or less parallel 

 to the strike of the vein, i.e., usually parallel to the 

 hill-slope wherever it may be. 



The displacements are seldom more than a few feet, and 

 the plane of faulting carries a good deal of gouge or 

 selvage matter. Where the vein ends abruptly it is 



