ASSOCIATED EOCKS AND ORES. 53 



a statement. Antimony accompanies cinnabar in Corsica and at Smyrna; 

 realgar and cinnabar are fonnd together in Persia. Realgar is one of the 

 exports of the qnicksilver region of China. Gold is intimately associated 

 with qnicksilver and cinnabar at a great nnmber of points, sometimes in 

 veins, but oftener in gravels. There is no deposit of great importance, 

 however, from which both metals can be profitably extracted. Ores of 

 copper and zinc are not seldom found with cinnabar; lead and silver ores 

 are more rare; but, as in the case of gold, it is seldom that valuable de- 

 posits of any of these metals carry important quantities of quicksilver or 

 that valuable deposits of cinnabar contain important quantities of the other 

 metals. It is nevertheless interesting to observe that, with the exception of 

 tin, all the chief metallic ores are sometimes deposited together with cinna- 

 bar. The gangue minerals accompanying cinnabar are nearly always either 

 silica, often in part of hydrous varieties, or carbonates in which calcite pre- 

 dominates. As Mr. d'Achiardi remarks, the character of the gangue seems 

 largely determined by the nature of the adjacent rock. Baryte and fluor- 

 spar are not infrequent and bituminous matter is found in a very large pro- 

 portion of quicksilver mines. 



Form of the deposits. — Exccpt ju the casc of gravels, I know of no case in 

 which it is clear that cinnabar has been deposited simultaneously with the 

 other material of stratified rocks. It is true that observers have not infre- 

 quently asserted of cinnabar deposits that they were coeval with the Inclos- 

 ing rocks, but the only ground for this opinion which I have seen given is 

 conformablllty between deposits of ore and the surrounding strata. This 

 is by no means adequate to establish the point in question. In most cases 

 it seems certain that tlie deposition of ore was subsetjuent to some disturlj- 

 ance of the country rock. In these cases the ore Is deposited in interstitial 

 spaces, and possiblv also to some extent by substitution for rocks or other 

 minerals. There is no doubt that true veins of cinnabar occur, sometimes 

 cutting sedimentary rocks and sometimes following the stratification. Re- 

 ticulated masses and Impregnations are also common. It is often supposed 

 that tlie characteristic forms of cinnabar deposits are not to be brought 

 under any of these categories ; but I cannot see sufficient evidence in the 

 literature to prove this supposition. Selvages and comb structure are often 



