﻿Some Ores and Rocks of Southern Slocan. 295 



district under consideration is composed of a granite 

 having the following characters. 



This granite is of a dark grey color and is composed of 

 quartz, feldspars, biotite and hornblende, with a good 

 deal of accessory sphene. 



Its striking visible feature, however, is the occur- 

 rence in it of large crystals of impure orthoclase, 

 giving it a porphyritic appearance. These crystals are 

 usually a half to one inch long, and are commonly 

 twinned parallel to the orthopinacoid. Small scales of 

 biotite are scattered through the crystals, and the 

 analysis, as here given, shows a good deal of lime and 

 soda for an orthoclase. 



SiO^ 59-86 



Al^ + FeA 20-26 



K,0 .* 12-39 



Na^O 5-76 



CaO 2-90 



MgO 0-78 



Total 101-95 



The lime is probably present as calcium carbonate. 

 An analysis of the granite gave : — 



SiO^ 60-09 



AlA 17-20 



FeA 6-73 



CaO 8-24 



Na,0 2-45 



K,0 6-23 



MsO -47 



Total 101-41 



A microscopical examination of a specimen of this 

 granite, taken from within a few feet of a quartz vein, 

 was made by Dr. Adams. It was found to be a crushed 



