367 



These general coincidences between the distribution of the minerals in the 

 two countries, I believe to be more than accidental ; and I only venture to 

 advance them in this imperfect manner to show that in both the Australian 

 and New Zealand mountain systems we have the same mineral fields repre- 

 sented on parallel lines, which lie at the same angle to the meridian in each 

 case ; and further that the peculiar features of each is repeated at equal 

 intervals, distinguished especially by the deterioration in the value of the gold, 

 as we pass northwards in both countries ; the only material difference being 

 that New Zealand is situated geographically nine degrees further south, than 

 that portion of Australia. 



Gold Mines. 



Gold was discovered within less than three years of the foundation of the 

 colony, in 1840, but it was not practically worked until 1852, when the mines 

 at Coromandel first attracted attention to the same district that at the present 

 time forms the chief seat of mining operations in New Zealand ; but the 

 yield from those mines has, up to the present time been small, when compared 

 with the quantity of alluvial gold obtained in the South Island, subsequent to 

 1861, at which date the gold fields of Otago became prominently known. 

 I have already alluded to the peculiarities of the manner in which gold is 

 distributed in New Zealand, and taking these as a guide we naturally divide 

 the gold fields into the following districts for convenience of description : — 



1. The Northen gold field. 



2. Nelson and Westland, or "Western gold field. 



3. Otago, or Southern gold field. 



The Northern gold field is situated chiefly on the west side of the Cape 

 Colville peninsula, but gold has also been obtained in small quantities on the 

 eastern side. The peninsula is a bold mountain ridge, having a mean altitude 

 of 2000 feet above the sea level, composed of slate rocks interbedded with the 

 eruptive rocks belonging to the Diorite series of the lower Secondary period. 

 These rocks form at least three well-defined belts crossing the peninsula 

 obliquely in a north-east direction, the depressions which separate them being 

 occupied by tufaceous deposits of volcanic ash, intermixed with ejected 

 fragments of rocks of various ages. These Tufas which envelope the older 

 rocks to an altitude of at least 1400 feet above the sea level, were deposited in 

 the Tertiary epoch, and form part of a formation that occupies a very extensive 

 area in the Auckland province. 



The district as yet tested by the miners is a very insignificant portion of 

 the whole area of the country, and the auriferous reefs which have been dis- 

 covered, are confined to a few isolated localities, in which the tufa presents a 

 very marked difference from its prevailing character, being a fine-grained rock 

 containing a large quantity of auriferous pyrites (Bisulphide of Iron) dispersed 

 through its substance in minute grains and imperfect crystals. This rock, 

 which from its proneness to chemical change decomposes freely, and frequently 

 contains Gypsum (Sulphate of Lime), is the characteristic bed-rock of the 

 auriferous lodes at the Thames and Coromandel. In all the auriferous areas 

 Diorite dykes intersect the tufaceous rock, and it is not yet satisfactorily deter- 

 mined whether the auriferous tufas should be considered to form part of the 

 Tertiary volcanic series, or a distinct formation intermediate in age between 

 them and the slate rocks of the district. The auriferous reefs are rarely well 

 defined, and consist chiefly of sub-crystalline quartz in which the gold is found 

 distributed through the compact portions as minute specks, or entangled in a 

 crystalline or dendritic form, where the quartz is open in its texture. On the 

 whole, the reefs appear to be richest in the decomposed rock near the outcrop, 

 which has frequently led to over-sanguine anticipations regarding some of the 



