Fauquharson. — The Platinum GrnveU of Orejmhi. 449 



This occurrence, of course, has a rather important bearing on the 

 history of platinum-deposits. As will be seen in the sequel, the vast 

 majority of occurrences of the metal are in detrital formations, and 

 usually all attempts to trace the metal back to its original habitat have 

 failed. Here, however, we have an actual case, borne out both by assay 

 and by chemical analysis, of the metal found to all appearances in situ, 

 and, further, in a quartz vein. The latter point also is remarkable, for 

 there seems to be a general consensus of opinion amongst those who have 

 given most time to the history of the occurrences of the metal that its 

 origmal habitat is an igneous rock. The rocks may vary from acidic to 

 ultra-basic in composition, but hitherto, despite the fact that Edison in 

 America, and Roscoe and Schorlemmer, have shown that the metal occurs 

 in rocks and reefs more widely than is thought, the occurrence in a vein 

 must be regarded as extraordinary, the only previous occurrences of a 

 similar nature being those at Tilkerode, in the Hartz ; at Minas Gerraes, 

 in Brazil ; at Santa Rosa, in Columbia ; at Beresovsk, in Russia ; and 

 at Broken Hill, in New South Wales, though the latter is a j^eculiar form- 

 ation, differing from the others in that it consists of the gossany outcrops 

 of veins in a country rock of schists^ gneiss, and quartzites. 



Of the second occurrence in Auckland very little is known. All that 

 can be found with reference to it is that about the year 1885 J. A. Pond 

 reported to the Auckland Institute the fact that the metal had been found 

 at a place called the Wade, situated about sixteen miles due north of Auck- 

 land City. The rock in the immediate vicinity of the discovery consists 

 entirely of a very dark serpentine, probably derived from the decomposition 

 of some bade or ultra-basic igneous rock. 



We shall now pass on to the second occurrence — namely, that in Nelson 

 Province. In the north-north-west of Nelson, just inland from Massacre or 

 Golden Bay, there occurs a series of mountain ranges. A brief description 

 of the comitry from a geological point of \dew is essential to the proper 

 understanding of the deposits. The following section illustrates the S'^ries 

 just mentioned : — 



Aorere 

 Valley 



Takaka 

 Valley 



WNW 



Fig. 1. 



1. Granite. 2. Gneiss. 3. Mica-schist. 4. Slates. 5. Hornblende-porph3Tite. 

 6. Serpentine. 7. Tertiary deposits. 8. Diluvium and alluvium. 



Applying this section to an ordinary map of the north of Nelson, we 

 see that the western shores of Blind Bay from Separation Point to the 

 mouth of the Motueka River consist of granite flanked by gneiss. Pro- 

 ceeding from the granite, we find on the top of the Pikikirunga Range 

 hornblende-schist intercalated with crystalline limestone. These ranges con- 

 tinue westwards as far as the Takaka Valley, where they are intercepted 

 by hornblende-porphyrite and serpentine. Garnet-bearing mica-schist con- 

 stitutes the highest peaks of the Anatoki Mountains, while further to the 

 west we have clay-slates or phyllites. The Aorere Valley and the Haupiri 

 Range belong to the clay-slate zone, and the Wakamarama Range also 



15 — Trans. 



