Cox. — On the Mineralogy of Neiv Zealand. 449 



which flowed across the country in quite a different direction from what 

 the drainage now follows, and remnants of these old deposits yet remain. 

 The cross-drainage which now prevails, has removed large tracts of these 

 cements, and, by a process of natural sluicing, concentrated the gold in the 

 beds of the creeks, some of which have proved fabulously rich. For a 

 description of all these workings and the different characters of the alluvial 

 deposits, I must refer the reader to the " Manual of the Mineral Eesources 

 of New Zealand," by Dr. Hector, now in course of publication. 



Platinum. 



Native Platinum, Pt, Pe. — This metalhas been found in a native state in 

 small flat grains of a steel-grey or silver- white colour, associated with gold 

 in alluvial deposits at Stewart Island, and with Zircons in the gold-wash 

 of the southern goldfields. It is also found under similar conditions at 

 the Collingwood goldfield, Nelson, but it has never yet been discovered in a 

 reef (Hector, Trans. N.Z. Inst., vol. ii., pp. 185, 371; Jurors' Eep., p. 403). 



Platiniridium, Pt, Ir. — Grains of this rare mineral have been obtained 

 from the gold-wash of the Takaka diggings (Hochstetter's New Zealand, 

 p. 107). 



Osmium and Ieidium. 



Osmium-iridium, Ir, Os, also occurs in the gold-wash of the Takaka 

 diggings as small flat grains, which are of a brighter colour and less mal- 

 leable than Platinum. They are mentioned by Dr. v. Hochstetter (New 

 Zealand, p. 107) and Dr. Hector (Jurors' Eeports, p. 403; and Trans. N.Z. 

 Inst., vol. ii., p. 371). 



Silver. 



But very little silver has yet been obtained in New Zealand except that 

 alloyed with gold, in which form, at the Thames, it occurs abundantly, and 

 as a component of the Tetrahedrite (Eichmondite) of Eichmond Hill, Col- 

 lingwood, in which sflver occurs in variable quantities up to 1792 ounces 

 per ton. It also occurs in all the Galenas in greater or less quantities. 



Native Silver, Ag, has been found as small rolled fragments in the 

 Eawarau and Wakatipu Lake diggings, and also at Waipori (Hector, Jurors' 

 Eeports, p. 403, 436). 



Argentite, Ag'. — Mr. E. H. Davis mentions the occurrence of a sulphide 

 of silver at the Silver Crown Claim, Thames (Geol. Eep., 1870-1, p. 61), and 

 a specimen is now in the Museum from that locality. It consists of a 

 blackish-grey powder, and as Mr. Davis gave no description of its mode of 

 occurrence I am unable to cite it. 



Pyrargyrite, Ag'^ Sb'" ; Proustite, Ag'^ As'". — It is probable that one or 

 other of these minerals occurs at the Thames, as Captain Hutton's mention of 

 the occurrence of " red oxide of silver" at the Golden Crown Mine (Geol. 



49 



