438 PROCEEDINGS OF SECTION C. 
the sea on the upper side of the fault, the amount of vertical 
displacement being about 300 feet. The effect of this will be 
better understood when it is stated that a bore put down from 
the Moanatairi tunnel, on the upthrow side of the fault, would 
explore lower country and reach the old floor or basement rock 
in a shorter distance than a bore put down from the foreshore, 
which has been carried down in recent times several hundreds of 
feet from its original position. Besides vertical downthrow, this 
fault has also caused a certain amount of lateral displacement, 
which must always be taken into consideration when conducting 
explorations from the low side to the high side of the fault. 
Besides the Moanatairi fault, there is what is locally known as 
the deach-slide. It appears that in driving from the mines on the 
foreshore towards the harbour a loose formation of shelly sands 
and gravels is met with, which has led to the belief that the 
country is cut off in this direction by a slide or fault. I am 
inclined to think that no fault exists along this line, the appear- 
ance being simply caused dy driving out of the country into the old 
harbour. 
3.—FPaleozoic—Te Anau Series. 
This formation forms the floor or basement rock of the peninsula, 
but it does not reach the surface within the limits of the Thames 
Goldfield proper, nor has it been reached in any of the mines. 
It crops out on the shores of the firth, about a mile north of 
Tararu stream, forming Rocky Point, whence it extends eastward 
to the upper part of Waiohanga Creek. It consists of blue and 
grey banded slaty shales, which are followed by yellowish-grey 
silicious mudstones, which seldom show distinct stratification, but 
are jointed in all directions, the joints being often stained or 
filled with yellow ocherous clays. Professor Hutton in 1869, and 
Mr. Cox in 1882, spoke of this mudstone as a felsite. In 1887 
the former re-examined this point, and in his paper on the “Rocks 
of the Hauraki Goldfields” states that he is now convinced of its 
clastic origin, a conclusion which I can fully endorse. 
These shales and mudstones are of uncertain age, as no fossils 
have yet been found in them, but they most probably belong to 
the Paleozoic period. At any rate, they bear a strong resem- 
blance to the rocks forming the Taupiri range, on whose flanks 
occur fossiliferous rocks of undoubted Triassic age. 
At the Thames the gold-bearing veins occur in the felspathic 
and tufaceous sandstones of Eocene age, at Taupo and Coromandel 
goldfields they occur both in the tufaceous sandstones and in the 
underlying slaty shales and mudstones. At Coromandel, for 
instance, we have the celebrated Kapanga mine in the tufaceous 
sandstone, and the Tokatea and Bismark mines in the slaty 
shales, near their junction with the overlying tufaceous sand- 
stones. 
