., -; : -, 



■ 



ORES AND MINERALS ASSOCIATED WITH THE GOLD. 



361 



The distribution of the gold in the gravel calls for a few remarks. Although 

 the phenomena of this distribution are generally of a simple nature, and such 

 as would naturally be expected to result from the disintegration and removal 

 by water of a large mass of auriferous rock, yet there are some puzzling 

 peculiarities, for which it is not easy to find an explanation. That a con- 

 siderable part of the gold should be either lodged directly upon the bed-rock, 

 or disseminated through the lowest layers of the gravel, nearly in contact 

 with it, is easily understood. The tendency of the very heavy metal to sink, 

 as the mass of detritus was being moved by the aqueous current, would be con- 

 tinually exerted ; and it is only the extreme fineness of the particles which 

 has kept even a small portion of it from finding its way as far down as to the 



solid rock. 



In certain cases there is no gold at all upon the bed-rock ; but such 

 instances are rare. There is nothing in these exceptional instances which 

 need excite surprise ; for that in certain localities there should have been a 

 covering of detritus spread over the surface of the bed-rock, coming from the 

 disintegration of a quantity of rock which contained no gold, is very natural. 

 It is not the case now r , nor has it ever been, so far as we can judge, that all 

 parts of the bed-rock have been impregnated with gold. Portions must 

 have been entirely barren, and if the debris of such masses happened to 

 find a permanent lodgment on the surface of the rock, and then become 

 more or less consolidated, the particles of gold borne from other and richer 

 regions would rest upon the underlying barren layers of gravel. 







Section VIII. — Ores and Minerals associated with the Gold. 



* 



Some statements have been made in the preceding pages * in regard to 

 the metalliferous ores which are most likely to be found accompanying the 

 gold in the quartz veins. Something now remains to be said about the 

 minerals and ores which have been detected in the gold-washings. These 

 substances can, of course, be only such as are not too brittle or too easily 

 oxidized ; for otherwise they would have been ground to powder in the 

 process of the formation of the gravel, and would then have rapidly disap- 

 peared, having been oxidized and dissolved away. If the metal gold is found 

 so w r idely disseminated through the gravel and in river sands all over the 

 world, it is because it is so very indestructible. It may be torn into very 



* See ante, pp. 56, 57. 



