92 Notes on the Auriferous Slate Sf Granite Veins ofN.S.W. 



adjoining rock ; but the difterence is so trifling that it would 

 easily pass unnoted unless attention were drawn to it. The 

 gold is deposited in fine flakes, like gilding on the faces of the 

 cleavage planes, where it has evidently been aggregated in its 

 present form, and not in conjunction with pyrites : neither is 

 there any sign of the latter ore having been collected in the 

 band in such quantities as to affect the gold deposit. 



In this close schistose rock there could be no currents of 

 water to carry the gold about in solution, neither is there any 

 passage through which it could have been forced up from some 

 unknown deep region. The sole explanation which could be 

 upheld is that it was formed by aggregation on the line of the 

 band, and derived from the adjoining rocks. 



Instances have been previously met with where the quartz 

 usually filling up the space between the walls of a vein had 

 been replaced by auriferous slate of exactly the same character : 

 but this is the first example of a large auriferous band of slate 

 which has been brought under general notice. 



The second case is a similar deposit of gold in granite bands 

 at Major's Creek, near Braidwood, but differing somewhat in 

 character. This district has a granite formation, traversed by 

 bands of hard crystalline schist, with every intermediate shade 

 of difference between this rock and the granite. 



The alluvial gold, is of the fine flaky character always marking 

 gold derived from the granite, but is accompanied by titani- 

 ferous iron instead of by stream tin. 



. At Major's Creek several auriferous bands of granite have 

 been discovered, and some are at present worked to profit. 



Grenerally, the bands are more or less decomposed ; but in 

 one face, where the band was thirty feet wide, it had undergone 

 little change, and was only distinguishable from the bounding 

 rock by its colour, changed through the decomposition of pyrites. 

 These bands are nearly vertical, with a westerly bearing ; and 

 have yielded from a trace up to one or two ounces of gold per 

 ton. The gold is of the same fine description as that taken 

 from the alluvial ground, and has originally been pyritous gold. 

 The rock is studded with cavities, retaining the form of the 

 crystals of pyrites, but now filled with brown oxide of iron, and 

 the gold liberated by the decomposition of the iron ore. 



At two points where the bands could be seen below the 

 water level, the pyrites was unchanged, and in such quantities 

 as to form a large percentage of the rock. Here the gold will, 

 no doubt, be enveloped in the pyrites, and a rough assay made 

 of the latter gave over an ounce of gold per ton. 



