ORES OF GOLD 
41 
indicator may consist of a band of tiny lenticles each Wong a 
cleavage plane. The deposition of the gold in the ar 
Opposite the indicator is probably due to the reduction o 
the gold solutions by the oxidation of the ferrous iron in 
the chlorite. The miner follows the indicators and extracts 
the quartz which intersects them. } 
The Ballarat East Mines are nearer the granite than those 
of Ballarat West, and their deeper origin is indicated by 
the more frequent occurrence of albite- 
felspar in the quartz. The Ballarat 
West lodes may subdivide below into 
irregular veins like those of the eastern 
field. 
Gold ores are especially characteristic 
of the pre-Palzozoic crystalline rocks 
which yield gold in many countries, and 
include in South and West Africa, India, 
Siberia, Australia, and North America, 
some of the most productive goldfields 
of the world. 
The Mysore Goldfield in Southern 
India (T. Pryor, Tr. ILM.M., xxxiii, 
1924, pp. 035-115) consists of pre- 
Paleozoic rocks, of which the founda- 
tion is mainly hornblende-schist. It 
has been invaded by masses of granite 
and gneiss, and by dykes of felsite. 
While these rocks were cooling the 
schists were fractured, and the fissures 
filled by dark, bluish-gray quartz-veins, 
which were widened by the replacement 
of the walls, residues of which remain . 
as actinolite, pyroxene, and brown mica. After the igneous 
rocks had become quite solid, N.N.W. faults broke througt 
the quartz-veins, and solutions from below introduce go 
Pyrites, arsenopyrite, blende, galena, and chalcopyrite. 3 
these solutions were pneumatolytic is shown by the abun oo 
tourmaline, and some scheelite. The gold was deposited in 
rich shoots where it entered the inclined usta, Su 2 
quently the country was broken by faults trending wo 
to S. and they were filled with further lodes containing