402 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Mar. 7, 



of this iron oxide can be traced to the pyrites in the lower parts of 

 the veins, to which the decomposition has not reached. 



This opinion of the formation of the native gold does not interfere 

 with the theory of the relatively new origin of the gold-bearing 

 quartz-veins themselves, but only has reference to the nature of the 

 distribution of the gold in the veins. At an early period after the 

 formation of the veins, the decomposition of the upper parts may 

 have gone on at a much quicker rate, assisted by hot-water springs ; 

 but the appearances at present seem to imply that this decompo- 

 sition is still being carried on, although in an imperceptible manner. 

 The barren quartz-veins belong to the same system with those bearing 

 gold, but are generally more compact, very rarely containing iron- 

 pyrites ; and their close structure allows of no decomposition. 



A great deal of the drift-gold is to be referred to the gold-bearing 

 quartz-veins. But the decomposed and disintegrated surfaces of 

 rocks containing iron-pyrites, such as hornblende-rock, syenite, dio- 

 rite, porphyry, and breccia in the Peel District, which contain pyrites 

 abundantly, although in small specks, are also to be regarded as a 

 source of gold. In several diggings here and in the Bathurst District 

 (especially at Barandong on the Macquarrie, near Wellington) gold 

 is found without any trace of quartz-pebbles, and can only be referred 

 to the rock itself. 



For the formation of a rich gold-field, however, the gold from 

 these two mentioned sources must have undergone a concentration 

 by drifting in water, in a strong stream moving heavy boulders and 

 depositing the gold in favourable situations, and partly cleaned from 

 the admixture of earthy materials. The formation of the drift-gold 

 is so well known, that there appears very little left to be said about 

 it. I will only remark, that the newest alluvial soil is observed to 

 be perceptibly richer near gold-bearing quartz-veins ; showing that 

 the disintegration, if not the decomposition, of these veins is still 

 going on. 



Besides gold, ores of copper and of antimony have been observed. 

 A high and remote hilly country of the " Peel River Land and Mineral 

 Company's" estate still remains to be minutely examined, and I look 

 for new discoveries there. Chromate of iron is found in large masses 

 in serpentine. Red oxide of iron {hcematite^ is of frequent occur- 

 rence. Magnetic and titaniferous iron is disseminated in minute 

 particles in the rock, and abundantly met with in the deposits of drift- 

 gold. Traces of precious stones — zircons (hyacinths) and corundum 

 (sapphire) — have been recognized*. I am very attentively looking 

 out for them, as for other discoveries, and I hope to be able to give, 

 in future letters, some farther observations, based on accurate chemical 

 assays, especially of the iron-pyrites contained in the quartz-veins 

 and in the rock. 



Cann's Plains, Peel River, New South Wales, 

 September 8, 1854. 



* [See also Mr. G. M. Stephen's paper on Australian Gems, Quart. Journ. Geol. 

 Sec. vol. X. p. 303.] 



