122 
GEOLOGICAL NOTES ON THE MITTA MITTA RIVER, 
NORTH-EAST DISTRICT. 
By E. J. Dunn , F.G.S., Director, Geological Survey. 
Leases for dredging have been marked out for several miles above 
Mitta Mitta township. Between the junctions of the Dark River and 
Wombat Creek with the Mitta Mitta there are a few miners working 
the alluvial deposits,. These alluvial gravels have been deposited at several 
different periods, but are all auriferous to some extent. 
The most recent gravels are in the river bed. From the Dark River 
upwaids there is a considerable fall in the bed of the Mitta Mitta River, 
and the rocks are exposed along the banks in the bed of the stream. At 
the end of the dry season the water becomes diminished in volume, and 
by means of wing dams the stream is diverted, and the crevices right in 
the river Ted are worked. This method of mining has been pursued for 
over forty years, but there is still a great deal of the bed that would give 
small wages if the crevices, were carefully cleaned up. Formerly rich 
patches were obtained, and even now some of those working on the river 
state that they get 2 grains of gold to the dish on the bars in the river. 
Besides the actual river channel there are alluvial flats along the river 
course, some of which have been extensively worked, and from which 
good yields are reported to have been obtained. There are other flats that 
have scarcely been tested, and these should in parts be worth working. At 
a higher level there are terraces, often 40 to 50 feet, and sometimes 100 
feet, above the water level. They are in many places extensive, and do 
not appear to have been much tried. Miners state that they all contain 
a little gold, but that it would be expensive to bring water to work them. 
Still higher up—as much as 300 feet above the river bed—alluvial 
workings have been carried on along the slopes of the hills for the purpose 
of gathering up the gold scattered over the slopes that has been set free 
from the old high level Cainozoic river leads. Mr. Forrest has done 
much work of this character, and he considers there still remains a large 
area of similar ground. At the upper portion of his workings he has 
traced the gravel under the basalt, which evidently filled a tributary of 
the main old lead. This Cainozoic sub-basaltic wash has not been fol¬ 
lowed beneath the basalt, but as the gold would be far more concentrated 
there than on the slopes, this work should be done. The wash is very 
heavy, and there are large boulders to deal with. Where it runs beneath 
the basalt it is 4 feet in thickness., and is covered by 7 feet of basalt. 
The floor is the remarkable agglomerate that forms so much of the river 
bed above Dark River. On the eastern side of the Mitta Mitta River from 
about J mile below the junction of Toak’s Creek up to the junction of 
Wombat Creek, basalt covers the higher portions of the country. It 
crosses over to the western side of the river a short distance above the 
junction of Wombat Creek. It occurs on the southern side of Wombat 
Creek, and for over a mile up that creek. 
Between Wombat Creek and Toak’s Creek is an extensive tract of 
Devonian conglomerate. The most western extension is at Limestone 
Gap. It crosses Wombat Creek a little above its junction with the Mitta 
Mitta River, and is generally bounded on the south by the limestone out¬ 
crops. It occurs as a bluff 200 feet high close to the limestone bluff on 
the Mitta Mitta, River. 
On the eastern side of the river the basalt occupies a large area. It 
appears to have originated to the north of Lake Omeo, and to have 
