( 303 ) 



Address delivered at the Anniversary Meeting of the Geologi- 

 cal Society of London, on 20 th February 1846. By Leonard 

 HoiiNER, Esq., V.P.R.S., President of the Society. 



(Concluded from p. 128.) 



Metallic Products. 



The protrusions of igneous rocks along the line of the 

 Urals were accompanied throughout a great part of the chain 

 by the formation of numerous and extensive metallic veins, 

 particularly on the eastern flanks, the chief seat of the me- 

 tallic riches of Russia, especially in copper and iron. The 

 geological details connected with these metalliferous rocks 

 constitute a large and interesting part of Sir R. Murchison's 

 work. One of the most important geological features con- 

 nected with them, and it is one which appears to be well 

 established, is the comparatively recent date of the eruptions 

 which brought these metallic products of nature's crucibles 

 within the reach of man. The accounts of the rich gold de- 

 posites are curious, and the ejection of the rock in which that 

 metal is contained appears to have been very modern — little, 

 if at all, anterior to the destruction of the mammoths, whose 

 remains are entombed in the gravel which is found every- 

 where in the depressions of the Ural chain, and which covers 

 vast regions of Siberia. The matrix appears to be quartz in 

 the form of veins ; but to find the gold in that state is ex- 

 tremely rare. It is found in lumps and grains that have 

 been rolled, mixed with other detrital matter. A lump 

 weighing about seventy-eight pounds English, found in 1843, 

 is now in the Museum of the Imperial School of Mines at 

 St Petersburg. 



Several curious facts are adduced to shew that some of the 

 ores of copper, particularly the green carbonate or malachite, 

 are aqueous productions, derived from pre-existing ores, as 

 calcareous stalagmites are derived from limestone rocks. 

 In the copper mine of Nijny Tagil sk, at a depth of 280 feet 

 from the surface, an immense irregularly- shaped botryoidal 



