Vol. 60.] GENESIS OF THE GOLD-DEPOSITS OF BAKKERVILLE. 389 



28. The Genksis of the Gold-Deposits of Barkerville (British 

 Collmi'.ia) and the Vicinity. By Austin J. R. Atkin, Esq. 

 (Communicated by the Secretary. Read April 27th, 1904.) 



The gold-bearing area of Cariboo is roughly confined within a 

 radius of 20 miles of Barkerville, to the band of varied crystalline 

 rocks known as the Cariboo Schists. 



These rocks show evidences of fragmental origin, notably below 

 the mouth of Stouts Gulch. They represent in all probability the 

 silt and detrital matter deposited in a deep ocean lying off the 

 shores of the ancient Archaean ridge, and are generally assigned 

 to the Lower Palaeozoic age. 1 They seem to have a tendency 

 towards fracture in a north-easterly direction, owing to pressure 

 exerted at right angles to their trend. 



The steep northerly escarpments of the mountains are to be 

 attributed to the inclination of the beds, favouring the erosive 

 action of adjacent streams. 



The whole schist-belt, with the exception of the mountain-tops, 

 is thickly covered with detritus of Glacial age and origin, which 

 obscures many features important to a thorough understanding of 

 the phenomena connected with the distribution of gold in this 

 district. 



The quartz-veins, exposed in those places where Glacial debris 

 have not covered the original rocks, are all of one general type, 

 although two systems of fracture traverse the country. Most of 

 these fissures are infilled with veins, the richness of which has 

 contributed to the wealth of the placers below. The most striking 

 feature of a district in which the placers are so rich is that the 

 reefs at the heads of the gulches and along the sides 

 are of very low grade. This has led to much speculation as to 

 the site of the original deposits from which the gold was derived. 



The chief characteristics of the reefs of both systems are : — 



(a) The veins follow the strike, but not as a rule the dip, of the enclosing 

 schists : an exception being the Forrest Reef on Proserpine Mountain. 



(b) The gangue is similar to that found with the nuggets in the creeks — 

 lustreless, milky-white quartz, sometimes sugary. 



(c) The mineralization is sulphide of iron, distributed in coarsely-crystalline 

 bunches throughout the reef. A little galena, low in silver, is sometimes 

 found; but rarely copper-pyrites, or blende. The average contents of 

 sulphide do not exceed 6 per cent. 



Some of the sulphides are of good value, but others are quite worthless. 

 Their quality cannot be determined, except by assay. Galena has not been 

 found to exert any beneficial influence on the gold-values of the reefs. 

 {d) All the reefs show very little oxidized ore, some none at all : which goes 

 to show that the present outcrops are recent exposures, and cannot have 

 been the original surfaces presented on the tilting of the schist-bed. 



1 The age of these rocks was determined by Mr. A. Bowman, of the Canadian 

 Geological Survey. 



Q. J. G. S. No. 240. 2 e 



