206 Dr. Mac Culloch on Mineral Veins. 



SULPIIURETS. 



Silver. Zinc. 



Copper; yellow, grey. Arsenic. Arsenic and iron. 



Lead, lead and antimony. Antimony ; red and grey. 



INIercury ; brown, red. Bismutli. 



Iron. 



The minerals which seem to carry the evidence of an aqueous 

 origin in their forms are the following : 



Earthy phosphat of iron. Stalactitical manganese oxyde, 



Stalactitical hsematites. red and black. 



Bog iron ore. Stalactitical calamine. 



Malachite. Stalactitical pyrites, whether of 



iron or copper. 



The last list is that which contains the minerals found in 

 secondary strata of aqueous deposition, and which do not 

 appear to have experienced the influence of fire. 



Gold. Oxydulous iron. 



Quicksilver. Iron pyrites. 



Muriat of quicksilver. Hematites. 



Sulphuret of quicksilver. Iron stones and ochres. 



Blue carbonat of copper. Cobalt ; black oxyde. 



Green carbonat of copper. Manganese ; black oxyde. 



All of these are found in the preceding enumeration ; so that 

 these situations only offer proofs in confirmation of the present 

 views. 



I must now proceed to examine the minerals, whether 

 earthy or metallic, which are the produce of igneous fusion, or 

 of sublimation from a state of vapour. The evidence respecting 

 these is also derived from two sources ; from chemical ex- 

 perience, and from their positions in rocks which are known 

 to be the produce of fire. These last may be limited to gra- 

 nite, the traps, and the volcanic rooks, though there seems no 

 reason to doubt that gneiss, micaceous schist, and other primary 

 strata might be added to these ; in which case the catalogue 

 might be still further increased. 



The earthy minerals which may be modified by artificial fire, 

 or which undergo the action of heat without destruction, are 

 the carbonats of lime, barytes and strontian, and the phosphat 

 of lime. Silica is sublimed in a crystalline form. 



Of the metallic minerals it appears that every metal may be 



