148 



ECONOMIC GEOLOGY 



According to H. Ries, the veins exhibit a curious uniformity 

 of direction, most of them striking nearly east and west, and few 

 of them departing more than 15 or 20 degrees from the vertical. 



a " 



a e 



They show considerable variation in width, ranging from a few 

 feet to 150 ft. where the altered country rock is impregnated with 

 chalcocite. In some instances there is no distinct hanging wall 





