538 New Zealand Institute. 



The collection illustrating industrial art in the colony has received further 

 additions hy 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 form in the above district is beyond doubt, but experience 

 shows that it is only under circumstances favourable for obtaining a sufficient 

 supply of water and a good fall for the enormous volume of debris, 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 Biver, 

 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 



