TRANSACTIONS OF SECTION C. 899 
conglomerates, and there is no field-evidence in favour of their origin as eruptive 
breccias. P Reet 
The conglomerates, however, are not all sedimentary in origin ; some of those 
included as banket are crushed quartz-lode, aud to this category belongs the rock 
which most resembles the Rand banket in general aspect. 
The conglomerates were examined by the author at various localities on both 
flanks of the old rocks that form the foundation of the present high veldt of 
Rhodesia. 
The Rhodesian ‘banket’ differs from that of the Rand in several important 
characters. The Rhodesian ‘banket’ is fluviatile instead of littoral in origin; the 
size of the pebbles is often much larger and less regular ; the pebbles varyjmore in 
composition, and the matrix is often a true schist. Moreover the author saw no 
adequate reason for correlating this conglomerate with the Rand banket, and regards 
it as older in age. 
These differences would render it easy to draw up a definition of ‘ banket? that 
would exclude the Rhodesian conglomerates; but the author thought that in 
practice the term had been used—as by Molengraaft, Hatch, and Griftiths—for sedi- 
mentary auriferous conglomerates, and he therefore considered that Dr. Sauer 
was justitied in applying the term ‘banket’ to the auriferous sedimentary con- 
glomerates of Rhodesia. 
2. The Indicators of the Ballarat Gold Fields : a Study in the Formation 
of Gold Pockets. By Professor J. W. Gregory, /.2.S. 
Complaint is often made against the Rhodesian gold fields on account of the 
patchiness of their gold. The Ballarat gold field is probably the patchiest of the 
leading gold fields of the world, and its history shows tbat such gold fields may be 
worked with economy and success after the discovery of the clue to the distribu- 
tion of their gold pockets. The Ballarat gold field is in Victoria, about ninety 
miles west of Melbourne. It includes three lines of reefs, placed en échelon, a mile 
or twoapart. The mines of Ballarat West are on big continuous quartz reefs in 
which the ore occurs in shoots. They preserted no special difficulty; but the 
central and the eastern lines, viz., Ballarat Kast and Little Bendigo, presented no 
such main reefs. The slates and sandstones of these fields are seamed with a com- 
plex of quartz veins. The famous nuggets of Ballarat were found on the surface 
along a line running north and south through the Ballarat Hast field; but until 
the miners had a clue to the distribution of the gold pockets in the reefs efforts to 
work the mines below the alluvial deposits were not rewarded with much success. 
It was at length noticed by Llewellyn that a gold pocket appeared to have 
been deposited at the point where a thin iron-stained line in the slates met a vein 
of quartz; he followed along this line, and found that where it intersected a quartz 
vein there was generally a rich pocket of ore. The quartz veins were barren, 
excepting where they met one of these iron-stained bands, Opposite them, for 
from six to eighteen inches, the quartz would be very rich. Elsewhere the quartz 
was barren. Llewellyn called these bands indicators, and they have been followed 
throughout the greater part of the Ballarat Hast gold field, the success of which 
has been largely due to their guidance. 
These indicators were at first described”as oxidised pyritic seams, and they 
have generally been regarded as sedimentary seams interstratified in the slates 
and quartzites of the country. This view has been widely expressed in mining 
literature. Bradford, on the contrary, maintained that they were not bands due 
to deposition, as he found that they crossed the bedding planes, The author has 
recently prepared a detailed account of the geology of the Ballarat gold field, 
including an account of the microscopic structure of the indicators. He finds 
‘that most of the indicators are seams of chlorite, and one of them is a narrow 
band of crowded rutile needles. Microscopic photographs, prepared by Mr. H. J. 
Grayson, were exhibited which conclusively proved the secondary origin of the 
indicators as they cross the bedding planes. They are in places composed of a 
