450 Tram^fwfion^. 



<onsist8 of slates. It is the Anatoki and the Haupiri Ranges which contain 

 the matrix of the gold and other metals found in the district.* As Hoch- 

 stetterf admirably puts it, " The gradual denundation of the mountains, 

 continued throughout countless ages, has produced masses of detritus, which 

 were deposited on the declivities of the mountains in the shape of con- 

 glomerates, and in the river-valleys as alluvial gravel and sand. In this 

 process of deposition, carried on under the influence of running waters, 

 nature herself has effected a washing operation, during which the heavier 

 particles of gold contained in the mountain detritus collected themselves at 

 the bottom of the deposits, and close to their source, so that they can now 

 be obtained by digging and washing." 



Such, then, is a brief outline of this district. The formations (alluvial) 

 in d fferent parts are geologically almost exactly similar, the only difference 

 being, o course, in the composition of the alluvium. For convenience, 

 however, it is found advisable to divide the alluvial district into three 

 parts — the Aorere Diggings, the Parapara Diggings, and the Takaka Dig- 

 gings. Of these, the one we are most intimately concerned with is the 

 Tatter, the Takaka. its position is indicated in the foregoing section. A 

 referenc3 to it shows that the diggings occur on the eastern slope of the 

 Haupiri and the Anatoki Ranges, and they comprise principally the three 

 •chief branches of the Takaka River. A section through a typical gold- 

 vbearing area appears as follows : — 



Fig. 2. 

 «. Clay-.slate or bed-rock. b. AuritVrou-i coiitilomeratc. r. .\llu\ ial sand. 



The conglomerate may be cemented by a ferruginous cement, or may 

 be quite uncemented, only loose sand lying between the bounders. The 

 lonnations, therefore, do not differ at all remarkably from those ordinarily 

 associated with gold-deposits throughout the South Island, and especially 

 in Otago, where the formations are commonly known as the " auriferous 

 -drifts." They have, however, one outstanding peculiarity which marks 

 them off from all other gold-deposits except those we have yet to describe, 

 and that is the occurrence in them of os'niridium and platiniridium in 

 snail grains of a tin-white colour. These occur with the gold in conjunction 

 with magnetite, ninne ous garnets, and titaniferous iron-ore (ilmenite). 



It is quite remarkable that though, as has been said, these auriferous 

 gravels are geologically similar in the district described in Nelson, and 

 though washing has been carried on, for instance, in the Aoreie Valley 

 for a long time, yet no occurrence of platinum or its alloys has up to the 

 present been recorded in any other area in Nelson than the Takaka. This 

 would tend to show that there is probably some peculiarity in the Takaka 

 surroundings ihat is absent from the other areas examined. 



* The above section is taken from Von Hochstetter's " New Zealand," p. 102. 

 t Von Hochstetter, loc. rit., p. 104. 



