THEOKIES OF OKE GENESIS. 445 



Ores are derived — 



From unknown subterranean sources: 



(1) B^' unknown means; 



(2) By distillation; 



(3) By solution, hot or cold, and reprecipitation. 

 From rocks such as occur on the earth's surface: 



(1) By unknown means, (a) source contiguous, {h) source 



remote ; 



(2) By distillation, (a) source contiguous, (b) source remote; 

 (B) By hot solutions, (a) source contiguous, (h) source remote; 



(4) By cold solutions, («) source contiguous, (b) source remote. 

 From the earth's interior: 



(1) By unknown means; 



(2) By distillation ; 



(3) B}' hot solutions. 



Objections to an infragranitic origin. — As lias bceu abuudautly provcd abovc, 

 either the quicksilver deposits of the Pacific Slope are derived by means 

 of hot solutions from the granite, which is contiguous to the deposit in the 

 case of Steamboat Spi'ings, but more or less remote in all other instances, 

 or else they are derived as heated solutions from the earth's intei-ior (the 

 region below the granite). Of this region we know but little. It sends to 

 the surface eruptive rocks and volcanic emanations, gaseous or in solution. 

 These emanations almost invariably escape in large quantities from the 

 same vents from which the lavas flow, but also often escape through fissures 

 at considerable distances from craters. Eruptive rocks sometimes contain 

 gold, silver, lead, and other metals, and it cannot be asserted that the}' may 

 not also carry quicksilver. But,' were the source of quicksilver nearly or 

 quite identical with the source of the lavas, one would expect to find more 

 or less quicksilver within the craters of the volcanic vents, from which sul- 

 phurous, boracic, and alkaline emanations must have issued. This is not 

 the case. At Sulphur Bank are three unmistakable craters, none of them 

 showing any trace of cinnabar, and tliere are ver}' numerous eruptive 

 masses throughout the quicksilver belt unassociated witli (piicksilver. So- 

 lutions of the heavy metals are also extremely unstable, their sulphides 



