On the Geological Distribution of Gold. 35 



of gold, "by disintegration." Palladium is well-known to be 

 a natural alloy of gold, in Brazil. 



Copper in a native state, in small, fiat particles, was found 

 by the writer in one of the early auriferous cliluvials of An- 

 tioquia, in South America, in the proportion of about 10 per 

 cent, of gold with the copper. 



Metallic Compounds found ivith the early fluvials producing 

 Gold. — Cinnabar, grey manganese, wolfram, wood-tin, and the 

 more common per-oxide of tin — this last being found 

 abundantly in Cornwall, some parts of South America, and 

 more recently in Victoria, Australia, &c. Sulphate of mer- 

 cury, titanite, negrine, rutile, prot-oxide of iron, magnetic- 

 iron, specular iron-ore, chromate of iron, and titaniferous 

 iron-oxidule — most of these compounds prevailing among 

 fluvials, and by the gold-seekers termed " black sand." 



The most valuable of gems or precious stones are found in 

 the auriferous diluvials of earlier date ; this apparently being 

 the period when these articles of wealth and luxury were 

 distributed (diamond and ruby). 



Having thus briefly noticed the peculiarities about gold, as 

 found in the rock, and this metal as encountered among the 

 early fluvial deposits, we will shortly dwell on the question 

 of the analogy between the two auriferous sources, and par- 

 ticularly with reference to the prevailing hypothesis for the 

 origin of fluvial gold, by the Spanish miner termed " oro- 

 corrido," and by the gold-seeker of modern times known 

 by the name of "wash-gold." 



Our first inquiry will therefore be — At what geological 

 period were the auriferous materials deposited in the rock, 

 in the form of a vein, as now actually seen? 



Supposing that the auriferous veinstone existed previous 

 to the tertiary era, may we not ask — how is the prevailing 

 total absence of gold in the detritus prepared and deposited 

 during the three earlier periods of the tertiaries, viz., the 

 Eocene, the Miocene, and the Pliocene to be accounted for ? 

 These formations were produced from disintegrated rocks, by 

 the agency of water, similar to the Pleistocene, when the 

 auriferous materials made their first appearance among the 

 fluvials. To the latter period a distinctive term, that of 

 " diluvial epoch," is applied, as representing the immediate 

 results of the last preparatory denudation which visited our 

 globe. Gold and precious stones were deposited on the 

 denuded rock at this period, and by this natural concentra- 

 tion are now easily found and removed. 



