GOLD. 531 



rocks. He finds, moreover, that in Russia, over an area larger than half Europe, the 

 palaeozoic rocks are not crystalline and only slightly solidified, and that they contain no 

 gold : Avhereas the same strata in the Ural chain, broken up and pierced by eruptive 

 rocks, and rendered crystalline, becomes highly metalliferous and auriferous. He thinks 

 the gold was not introduced till after the tertiary period, and he suggests that the same 

 may be true of all the great gold deposits on the globe. 



The facts adduced by Sir Roderick certainly make it very probable that gold was not 

 introduced into the Russian rocks, till the time of their metamorphism, which he would 

 make more recent than the tertiary. Probably it was metamorphism that introduced 

 this metal into other strata : but the period of metamorphism may have varied a good 

 deal, in different parts of the world. We have no means of determining the period in 

 Vermont, only that it was probably more recent than the carboniferous period. 



But the most difficult point to settle is the manner in which the gold has been intro- 

 duced into the rocks. It could not of course have been introduced in its metallic state, 

 unless it were converted into vapor. And some have indeed imagined it to have been 

 sublimated from the intensely heated interior. But how that would disseminate it through 

 quartz in grains too small for the naked eye, or on the other hand cause it to collect in 

 nuggets of forty or fifty pounds, is beyond our conception. It has been more plausibly 

 suggested, that the quartz veins containing the gold were injected from a molten mass 

 beneath, through which the metal was diffused. But the idea of bringing pure quartz 

 into a molten state in the earth, is absurd, since the most intense heat scarcely melts it at 

 all. Moreover, if we could in this way introduce the gold into the veins, yet this would 

 not carry it into the folia of the schists, where often it is found in large quantities. In 

 short, we can conceive of no mode in which dry heat alone could bring up gold from the 

 melted interior, and disseminate it through the rocks in a metallic state. 



On the other hand there are difficulties in the hypothesis which would introduce it in 

 the wet way. The chief one is, that we do not find in nature any compound of gold that is 

 soluble in water. The brief remarks of Bischof on this subject, however, have a good 

 deal of weight in them. He says, "the occurrence of gold as small crystals, and as 

 capillary masses, is indicative of processes of reduction from compounds ; and its frequent 

 occurrence in quartz indicates the deposition of such gold compounds ; from the water 

 that deposited the quartz. There seems to be an intimate connection between gold and 

 iron, either in the state of sulphide or oxyd, and likewise between quartz and gold. A 

 silicate of gold may be prepared artificially, and it appears that under certain circum- 

 stances it may be dissolved in considerable amount. The silica constituting the 

 quartz associated with gold, certainly originates from the decomposition of silicates in 

 rocks, and it may be conjectured that the gold has the same origin possibly existing 

 as silicate." 



We hope our friend Dr. Homer Holland, of Westfield in Massachusetts, will excuse us 

 for making some extracts, on this subject, from private letters. Coming from one so well 

 known for his thorough chemical knowledge, and who has had such extensive opportuni- 

 ties for examining gold regions, we feel as if his opinions were of more importance than 

 our suggestions, especially as some of them have an important bearing upon the 

 auriferous deposits of Vermont. 



