BY LEO A. COTTON. 503' 



An occurrence which is quite rare in tlie mine, is the presence 

 of molybdenite. A small piece of that mineral, about the size of 

 a shilling, was found on the north side of the Conrad Lode, at 

 its junction with the King Conrad Lode. There is no evidence 

 of cassiterite or allied minerals in connection with this discoverA'. 

 Small pieces of molybdenite were also found in the adit-level, and 

 in the 100-feet level, at the Conrad Shaft, The wall-rock bound- 

 ing the Conrad Lode has not been altered to any great extent. 

 It has been impregnated for a few inches, chiefly with arsenical 

 pyrites and sericite, but the change is not very marked. 



The Genesis of the Deposits. 



It has been shown that, though the bearing of the King 

 Conrad Lode corresponds to a well marked fissure-system in the 

 Tingha area, some ten miles to the east, yet that of the Conrad 

 Lode is quite unique in direction. It is well established that 

 the tin-deposits are due to the ascent of heated vapours and 

 liquids along lines of fracture; and hence, had the Conrad fissure 

 been in existence at the time of the formation of the tin-beariiifr 

 veins, it is inconceivable that it could have escaped alteration by 

 the tin-bearing solutions. Hence it is fair to assume that this 

 important fissure is younger than the tin-veins. 



Again, it is probable that the King Conrad fissure was initiated 

 contemporaneously with the corresponding set of^fractures in the 

 Tingha area, but that it remained closed until crossed by the 

 heavier Conrad fissure, for it would appear that both lodes have 

 been formed simultaneously. It has, been mentioned that the 

 Conrad Lode lies at the margin of a large tin-bearing district, 

 and this must not be overlooked in considering the origin of the 

 deposits. 



The occurrence of cassiterite in association with metallic 

 sulphides is by no means uncommon. In a previous paper,* I 

 have mentioned several instances; and these I would here reca- 

 pitulate, in order to trace a connection between tin-veins proper 

 and silver-lead veins. 



*Loc. cit. 



