Fakquiiarson. — The Platinum Gravels of Orepvhi. 481 



To sum up : We have seen that this, the chief occurrence of the metal 

 in the South Island, is in an alluvial district near the sea-coast, with a gentle 

 slope towards the sea-boach, and situated at the base of the most outlying 

 spurs of a mountain-range. \\^e have seen that, contrary to what was to be 

 expected, the platinum does not originate from the gabbro rock directly 

 above which it is found, and which occurs all over the neighbourhood. We 

 have given reasons for believing that it may originate in the serpentine 

 region near the head of the Waiau, a region from which most of the tribu- 

 taries of the river derive their water ; and we have endeavoured to show 

 that if such be the case it would be quite possible for the metal in the form 

 of fine scales to be swept or worked along the beaches, and ultimately find 

 itself in the position it now occupies. If the theory is true it will be quite 

 iu accordance with observations made hi platiniferous regions the world over, 

 though it must be admitted that the fact that the metal actually occurs as 

 a constituent of beach-sands derived from a source far distant, and does not 

 originate in the basic rocks wliich occur all round it, is quite peculiar, and 

 one might almost say unique. 



From the economic standpoint, if the case is as we suppose, the value of 

 the discovery cannot be very great as far as the mother rock is concerned, 

 for ages of denudation and concentration will be necessary to make even 

 alluvial deposits payable, and it is almost impossible to think that it would 

 pay to crush a mother rock which furnishes, even after a tremendous length 

 of time, detritus giving such comparatively small returns. The theory, 

 however, enhances the probability of further discoveries of heavy particles 

 of the metal towards the mouth of the Waiau. 



Literature. 



It only remains now to give a synopsis of the literature to which we have 

 had access, and in this connection especial mention must be made of the 

 l)aper on the platinum group of metals by Professor J. F. Kemp (see below). 

 The references are divided into two groups — («) those relating more to the 

 geology of the country ; (6) those relating more particularly to platinum. 



[a.) Geological. 



" River Development." Professor J. C. Russell. 



Ifochstetter's " New Zealand," p. 101 et seq. 



" Transactions of the New Zealand Institute," vol. 15, 1882, pp. 419-20 ; 



vol. 18, 1885, pp. 402-4 : vol. 6, 1873. pp. 272-83 ; vol. 14, 1881, p. 449 ; 



vol. 7, p. 444. 

 •• Reports of the Geological Survey of New Zealand." 1866-67, pp. 29-30: 



1874-76, p. 177; 1871-72, pp. 91-112. 

 '■ Quarterly Journal of the Geological Society," 1885, pp. 212-13. 

 " Handbook of New Zealand," 1883, p. 36. 

 ■■ Sketch of New Zealand Geology." Captain Hutton. (" Quarterly Journal 



of the Geological Society," 1885, p. 191 el seq.) 

 " Outlines of New Zealand Geology." Sir James Hector. 

 •• Geological History of New Zealand," 1899. Captain Hutton. 

 •• Goldfields of New Zealand." A. McKay. 

 Admiralty Chart of New Zealand, No. 2553. 



Papers and reports relating to New Zealand minerals and mining, 1880-1904. 

 Gordon's " Miner's Guide," p. 59. 



16— Trans. 



