41 
Other reefs marked on the plan are the Hastings, the Scrubby, and 
the Eagle, situated to the south of the (Caledonia Consols, the Black Swan 
to the south-east of the Caledonia mine, and the Bendigo, a little to the 
south-east of the Caledonia South. Dyke workings are seen on the hill¬ 
top directly to the east of the Caledonia. For yields, workings, &c., see 
reports mentioned below. 
Felspar associated with the quartz reefs was noted at several of the 
mines, probably indicating the presence of small dykes other than the 
main north-west and south-east line, and adjacent to each reef. The 
Caledonia case is one example. 
The reports mentioned below on this area and its reefs, leave but little 
for me to add : — 
E. J. Dunn, F.G.S., Caledonia mine, Warrandyte. Rec. Geol. Survey, 
Viet., Vol. II., pt. i, pp. 50-51, 1907. 
R. A. F. Murray, F.G.S., Report on the Warrandyte Gold-field. 
Special Report, Department of Mines, Victoria, 1896. 
W. Forbes, Report on the geological survey of W T arrandyte. Progress 
Report, Geological Survey, Victoria, No. IX., pp. 47-48, map and 
sections, 1898. 
Other plans to the north and south of this area are:—Geological plan 
of Nillumbik by O. A. L. Whitelaw. Geological Quarter-Sheet 40 N.W., 
Warrandyte-Ringwood, by R. A. Moon, B.E. 
[Report sent in 24.4.0 7 .] 
THE GENERAL FEATURES OF THE JAMIESON GOLD-FIELD 
AND SOME MINES BETWEEN JAMIESON AND WOOD’S 
POINT. 
By E. ]. Dunn , F.G.S., Director , Geological Suroey. 
The Jamieson Gold-field. 
The country rock that prevails in the Jamieson district is Upper 
Silurian in age and at least portion of it appears to belong to the upper 
zones, such as those found at Walhalla, but not the very highest, which 
usually consist of mudstones and limestones. No sign of these was noticed. 
The usual rocks are slates, sandstones, and silty beds, and they must 
represent a very great thickness, taking into account the mountainous 
nature of the country and the manner in which these corrugated beds have 
been !carved out to form the present valleys. 
In this great thickness of sandstones and slates certain zones are pro¬ 
ductive of gold where the other conditions are favorable. Other zones 
are barren whatever the other conditions may be, and the recognition of 
these barren and productive zones is of primary importance. They should 
be mapped out, and in this way a considerable service would be rendered 
to mining, for in actual experience it is found that if all the other com 
cations are favorable in the productive beds, then gold is obtained, but 
if all the other conditions are favorable in a barren zone there is no gold 
present. 
Dioritic dykes are a prominent feature in connexion with the gold 
mines of this district. At Raspberry Creek the Ai mine is in an enlarge¬ 
ment of one of these dykes. Many of the other mines are dependent 
on the contact of the dykes with the reefs for the gold they furnish. Even 
where the dykes occur, unless all the other conditions exist, little or no gold 
is found. If there are reefs in the productive zone, but no dykes, there 
is no gold in certain cases. If the dykes cut through productive country, 
