538 New Zealand Institute. 
The collection illustrating industrial art in the colony has received further 
additions by a valuable donation of terra-cotta ware, made by Messrs. Boyd, 
of Auckland, the detailed list of which will appear in next year’s report. 
Amongst the articles sent from the Museum, either as presentations or 
exchanges, may be mentioned a collection of New Zealand auriferous quartz 
to the Perth Museum ; a large collection of rocks, fossils, and casts to the 
Oamaru Museum; New Zealand tanning barks to Messrs. Lightband, Allen, 
and Co., Christchurch, and to Messrs. Krull and Co., Wellington. 
GEOLOGICAL SURVEY. 
During the past year the survey has been extended in various districts, 
and the result embodied in reports, illustrated with maps and sections, which 
are published, as is usual, in a separate form. A stay of some weeks in the 
interior of Otago, in connection with the observation of the transit of Venus, 
afforded me an apportunity of re-examining the auriferous gravels and the 
associated strata of the Manuherikia and Upper Clutha Plains. The result 
confirmed my first expressed opinion that the excavation of these wide 
valleys dates from a very early period, and prior to many important dislo- 
cations of the basement rocks. Further, that the deposits by which they 
‘have been filled up belong to various ages, and that the source of the alluvial 
gold is to be found in the earliest formed of these deposits—in which the gold 
is irregularly distributed, so that it can only be extracted by the process of 
hydraulic mining. That enormous quantities of alluvial gold still remain 
untouched in this forth in the above district is beyond doubt, but experience 
shows that it is only under ci t favourable for obtaining a sufficient 
supply of water and a good fall for the enormous volume of débris, or tailings, 
that the gold can be profitably extracted. At Tinker's Gully, Drybread, 
St. Bathans, and other places along the west side of the Manuherikia Plain, 
the older auriferous gravels have been tilted at high angles, and thus brought 
into a favourable position for being worked. In other places where they are 
below the general drainage level of the basin, although equally rich, they 
could not be profitably worked. 
For hydraulic mining abundant water-supply is required, and could 
without much difficulty or expense be obtained from the Clutha River, 
which has a sufficiently rapid fall to afford power to raise part of its own 
water to an altitude that would command the terraces. Any expenditure 
for such a purpose would be of great ulterior advantage to the district, as 
there are very considerable tracts of land suitable for agricultural occupa- 
tion if they were irrigated. The proof of this is to be seen in many parts of 
the district where water-races abandoned by the miners have been utilized 
for gardens and fields with the most gratifying results, even when the soil 
presents no marked superiority. The dry climate, and marked difference of 
