480 Transactions. 



by heavy sea-action. All the projections, sucli as Pahia Point. Oraka 

 Point, Wakapatu Point, are denuded on their Avestern sides, and the sea 

 takes a bend round their eastern sides, forming a comparatively quiet bay. 

 All the beaches down to Wakapatu are strewn with j^ebbles, and an ex- 

 amination of these pebbles shows that they consist of pegmatite, granite 

 diorite, and a white mica-schist. These rocks all occur on the western 

 bank of the Waiau, and are not found anywhere on the intervening country. 



The fact that hardly any platinum has lately been found on the coasts 

 past Orepuki also strongly supports the theory, for owing to its high specific 

 gravity the metal would be amongst the very first to be deposited, and so 

 would, in ordinary circumstances, not be carried far. Further, the metal 

 has been found at the mouth of the Waiau not only in finer scales, but 

 in nuggets weighing 2 oz. or 3 oz. These would naturally be dropped as 

 soon as the velocity of the stream, from any cause, began to slacken ; or, 

 rather, as soon as the fall of stream began to be not so great these would 

 ceased to be rolled along the bed. 



It must be remembered, too, that in the Orepuki district the metal 

 occurs chiefly in the form of scales. These are especially capable of being 

 transported by water owing to the flatness of their surfaces, and the large 

 amount of surface therefore exposed to any propelling agency. 



Lastly, the theory affords an easy explanation of the fact that the 

 platinum in the claim is found invariably on or very near to the decom- 

 posed outer zone of the gabbro bed-rock. Owing to its weight it would 

 be deposited first of all on the beach-sands, nor would it be as liable to 

 subsequent removal by water-action as the sand above it. Of course, 

 even if it had come from the gabbro rock, and had been at first located 

 in, say, the sandstone, it would ultimately reach the bottom in accordanci^ 

 with the principle observed in almost all alluvial areas — i.e., the (so to 

 speak) burrowing-action of the precious metals by which they work their 

 way down from the highest level until they are stopped l)y impenetrable 

 material. 



It may here be stated that W. 8. Hamilton considers the origin of the 

 platinum as identical with that of the gold — viz., Ihe " nietallization " 

 of wood into a platiniferous substance, from Avhich the metal is derived 

 by some oxidation or replacement. This, of course, would presuppose? 

 the existence of platinic solutions, or salts of platinum capable of being 

 volatilized, quite near to the locality. With regard to this. Professor 

 Meunier has stated that by introducing volatilized chlorides of iron, nickel, 

 platinum, &c., together with hydrogen, into a porcelain tube heated to 

 redness and containing fragments of pyroxene, olivine, or rock, he is able 

 to deposit the metals or alloys of several metals in the interstices in such 

 a way as to imitate closely the natural occurrences. He therefore con- 

 cludes that the native platinum has been brought in presumably a similar- 

 manner, and has been deposited so as to yield either nuggets or grains (see 

 " Comptes Rendus de la. VII Session Congres Oeologique International," 

 p. 157). 



It certainly is rather interesting to knoAv that metals or alloys can be 

 deposited in this way ; yet crystallization from fusion seems not only to be 

 as competent to bring about the observed results, but also to have much 

 greater claims to probability and to general confidence. 



With Hamilton's theory, too, the question why tAvigs alone liaA^e been, 

 chosen as the basis for " metallization " requires an ausAver. 



