66 Transactions. 



Park, James — 



"Green's Reef, Ophir." Geol. Explorations, 1888, p. 17. 



" White's Eeef. Old Man Range," Geol. Explorations. 1888, p. 32. 



Alexandra Antimony Lode," Geol. Explorations, 1888, p. 33. 

 " Economic Geology of the Alexandra Sheet," Bull. No. 2, N.Z.G.S., 

 1906, p. 21. 



Rickard, T. A.— 



"Goldfields of Otago," Trans. Am. Inst. Min. Eng., vol. xxi, p. 411. 

 Eowe, W. E.— 



"Antimony Lode at Hindon," Geol. Explorations, 1879-80, p. 153. 



"Antimony Lode, Waipori," Geol. Explorations, 1879-80, p. 155. 



"Waitahnna Copper Lode," Geol. Explorations, 1879-80, p. 156. 

 Ulrich, G. H. F.— 



"Goldfields of Otago": Dunedin, 1875. 



" Handbook of New Zealand Mines," 1887, 1906. 



Geology of the Goldfield. 

 (a.) Geological Formations. 



The main formation of the goldfields and the country rock of the veins 

 is a foliated schist of considerable thickness. It varies locally, but for the 

 most part it is a mica-schist, more or less quartzose, and only submeta- 

 morphic in its upper portions. 



The schists have been described by Hutton as forming an anticline 

 whose axis runs south-east from Lake Wakatipu to Dunedin, with a syncline 

 on either side of it.* Along the axis of the anticline, where denudation 

 has been most active, are exposed the lowest and most metamorphic beds, 

 while younger and semialtered slates and phyllites are preserved in the 

 adjacent synclines. As we pass north-east or south-west we come on 

 younger rocks (conglomerates and greywackes), and -finally reach fossil- 

 iferous beds at Kurow in the north-east, and in the Hokonui Hills in the 

 south-west. The former have been classed as Permo-carboniferous,t and 

 the latter as Triassic and Jurassic. J The age of the schists has as yet been 

 little more than guessed at, and no systematic attempt has been made to 

 ascertain their relation to the above fossiliferous beds. The quartz veins 

 are confined to the schistose rocks, but this is evidently an effect of the 

 distribution of the fissuring-force. and not due to a different age of rocks. 

 It will be sufficient at present to regard the gold-bearing series as of middle 

 and upper Palaeozoic age. 



The schists are traversed by a number of structural faults, running for 

 the most at right angles to the axes of the folds described by Hutton, or 

 north-east and south-west. The faults have been mapped by McKay ,§ and 

 described later Ijy Park.|| It is open to question, however, if they are so 

 dominant and easily traced as these writers claim. This much seems 

 evident — namely, that the schists are much faulted, and that the faults 

 have roughly the direction stated. 



* Hutton, " Geology of Otago," 1875, p. 30. 



t Park, " Permo-carboniferous Rocks at Mount Marv," Trans. N.Z. Inst., vol. xxxvi, 

 p. 447. 



$ Hector, '^ Outline of New Zealand Geology" (Wellington, 1S86), p. 83. 



§ McKay, " Older Auriferous Drifts of Central Otago"' (Wellington, 1897), p. 107. 



II Park, Bulls. 2 and 5, N.Z.G.S., 1906, 1908. 



