135 
Notes on the Characters of the Adelong Reefs. 
By 8. Herserr Cox, F.CS., F.G:S. 
[Read before the Royal Society of N.S.W., 4 November, 1885.] 
THE main object of this paper is to place on record a somewhat 
interesting feature which can now be observed at the 1,000-feet 
G . : 
eventually be of importance in determining the period during 
which the gold-bearing reefs of the district were formed. 
The Adelong reefs traverse a belt of granite, from 6 to 8 
wide, along a north and south course—the granile upheaval 
also having followed a north and south line—and they are most 
excellent illustrations of true fissure lodes. 
The gangue from which the gold is extracted is quartz, but this 
quartz is distributed somewhat irregularly through soft chloritic 
rocks, which are themselves portions of the main lodes, and are 
known locally as channels of countr 
easting, and gradually leaves the main fissure. The reefs vary in 
their underlay, some heading to the east and others to the west 
while in other cases they are vertical. 
is a common impression in ee district that the difference 
in ‘ciceinng 4 is due to the surface features of the groun that 
the lodes always dip under the hills 3 but although this is 
apparently true in effect, the formation of the hills themselves has 
of course exerted no influence on the character of the reefs. 
€ granites are traversed at places by veins or dykes of diorite 
and hornblende syenite, which is probably a metamorp. 
diorite, and what I have to call attention to is the occurrence of 
one of these veins at the 1,000-feet level of the Great Victoria 
ine. The plan and section attached will illustrate the occurrence 
of this vein. The lode bifurcates at a short distance to the south 
of the main shaft; and after the main channel had been driven on 
for some distance and found to be unpayable, a cross cut was 
entered to the eastward to intersect the other branch. cross 
