98 GEOLOGY OF THE SECOND DISTRICT. 



Stating facts than giving theories. Every day brings to hght new facts wliich bear upon this 

 question ; and it would be premature now to expect to present a view, in the present stage 

 of mining operations in this country, which will be free from objections. All, therefore, 

 which ] would upon the whole be understood as saying, is, that so far as facts have been 

 revealed, they go to the support of the igneous origin of these ores. 



In this place I deem it important to say one word on the uncertainty of mining operations, 

 when carried on in connection with rocks whose origin is similar to that of serpentine and 

 primitive limestone. E.xperience has shown us, that every visible particle of ore may be 

 removed from those rocks, without leaving a trace by which the miner may push forward his 

 operations. Frequently in gneiss the vein diminishes in width, till it is a mere string ; but 

 this serves to direct the operations farther, and which, if pursued, lead to its enlargement or 

 exjjansions ; or sometimes a lateral shift throws the vein to one side. In either of these in- 

 stances, the miner is not left without rules and guides by which to recover a lost vein. Not 

 so, however, in the veins or masses in serpentine and primitive limestone. The whole mass, 

 after being quarried out, leaves no trace of the direction in which it may be found. There 

 is neither a string or line of ore, nor a shift, as in mines in other rocks. The probability is, 

 that abundance still exists ; but in what direction it is to be found, cannot be told. 



An examination of all the relations of the rocks, and of collateral facts, lead to the assump- 

 tion that a quantity of the ores was inclosed in a moulten mass of limestone or serjDentine, 

 wliich completely insulated it from the great reservoir from which it was derived. There 

 may be many instances in which the insulation is incomplete ; a narrow neck may remain, by 

 which the great mass may be discovered. The large masses, such as the Kearney and Parish 

 beds, have not been explored sufficiently to test this question ; but many small ones have been 

 entirely removed, without any evidence of an extension in any direction, or of a connection 

 with a larger mass beneath. Facts of this kind are very important to be known, and should 

 lead to caution in the investment of capital, either in the direct purchase of the mines them- 

 selves, or the erection of establishments for the manufacture of iron. 



