Boult. — Occurrence of Gold at Harbour Cone. 427 



Grains. 

 Ore ground to pass 100-mesh sieve . . 1,000 



Sodium-carbonate (Na 2 Co 3 ) . . . . 1,500 



Borax (Na„B 4 7 ) . . .. .. 750 



Litharge (PbO) . . . . . . 1,000 



Powdered charcoal (C) . . . . . . 20 



the silver value of the litharge being subtracted from the weight 

 ot the bullion. 



With each three assays a blank was run. Broken glass 

 was powdered in the same mortar and on the same buckling- 

 plate, and put through the same sieve and then assayed with 

 the same charge. The result was the silver value of the litharge 

 only, thus proving that no gold or silver had been introduced 

 through the agency of the apparatus used. 



General Geology. 



The rocks of the Otago Peninsula and of its neighbour- 

 hood are in three distinct groups : (1) The basement schists 

 of Otago ; (2) the Tertiary sandstones ; (3) the volcanic rocks 

 of the Peninsula. 



The schists of Otago form the vast pene-plain constituting 

 Central Otago. Pound the edges of this plain they are over- 

 lapped by beds of various ages, in all classes unconformably. 

 The schist country commences at Brighton, about eight miles 

 to the south of Dunedin. The schists are micaceous and -\sery 

 rich in epiartz folise and veins. In places mica-schist gives 

 place to chlorite -schist, usually in bands. Immediately north 

 of Brighton the highly denuded surface of the schists dips 

 beneath the Tertiary sandstones, which are almost horizontal. 

 The foliae of the schist itself are as a whole nearly horizontal 

 in this area, though often showing local plications. The sur- 

 face of the schists is undoubtedly the basement on which the 

 Tertiary sandstones and volcanic rocks of the Peninsula were 

 laid down. Dr. Marshall has reported fragments of schist 

 occurring in the Port Chalmers breccia thrown up at a late 

 stage of the eruptive period of the Peninsula, which proves 

 that these rocks exist somewhere beneath. Thus this schist 

 clearly underlies the Tertiary sandstones and volcanic rocks 

 of the Peninsula, and it is on their highly denuded surface that 

 the next series, the Tertiary sandstones, occur. The age of 

 these schists is not yet fixed certainly. The two authorities 

 on the matter are Sir James Hector, F.P.S., Director of the 

 Geological Survey of the colony, and Captain Hutton, formerlv 

 Provincial Geologist of Otago. The former, in his " Outline 

 of New Zealand Geology," which forms a summary of the work 

 done by the Geological Survey Department, calls these rock? 



