72 FORESTRY INT EASTERN RUSSIA. 



with the exception that the slope in this hemisphere is to 

 the west and the escapement edges of the deposits to the 

 east. So far as has been yet ascertained, the drift of the 

 Ural mountains seems to have its parallel in that of 

 Australia, which is all local, and much of it fluviatile, 

 deposited at the ancient mouths of the present rivers when 

 the country was at a lower level. The phenomena pointed 

 out by Captain Sturt render it far from improbable that 

 the interior depressed area of Australia is of similar 

 character to the great Aralo-Caspian country. From these 

 and other facts communicated to the Geological Society, 

 Sir Roderick predicted the probable mineral wealth of 

 Australia, and in a letter addressed to Sir C. Lemon, and 

 published in the PhilisopJiical Magazine, was the first to 

 advise that a person well acquainted with the washing of 

 mineral sands should be sent out to Australia, speculating 

 on the probability of auriferous alluvia being abundant in 

 that region. 



'In the paper read before the British Association 

 already referred to, Sir Roderick adverts to the distinctions 

 between such surface mining operations as those of Siberia, 

 California, and the Brazils, and those works in which, 

 besides the ores of silver, copper, &c., gold had also been 

 extracted from the veins in the solid or parent rock, as in 

 Mexico. Sir Roderick also traces the history of gold and 

 its development as known to the ancients and oar ances- 

 tors of the middle ages ; and shows that in all regions 

 where rocks similar to those he had described occurred, 

 there gold had been found in more or less quantities ; and 

 that just in proportion to the time that a country has been 

 civilised has the extraction and produce of the precious 

 metal diminished ; so that in many tracts where it formerly 

 prevailed to some extent, it has been either worked out 

 or the mines have been almost forgotten/ 



'Considering the short space of time which has elapsed 

 since the conquest of Siberia/ writes Sir Roderick 

 Murchison, ' and up to how recent a time these mountain 



