ITS APPLICATION TO MINING. 7 







also found in alluvial deposits, their original source being, 

 probably, the same as that of gold ; while iron in this 

 country is usually associated with coal and limestone, with- 

 out both of which substances it would be impossible to 

 reduce this valuable ore to a metallic state. 



The veins of mineral substances are by no means of equal 

 extent or value in all parts of their course, but the ore is 

 distributed in local masses and aggregations, or lunches, 

 along the line of its occurrence ; while in the case of tin it 

 occasionally spreads out into a flat mass, technically called a 

 floor, or on the other hand thins into mere filaments or strings, 

 and occasionally dies out altogether, leaving the miner to 

 infer the path he should pursue from the occurrence of vein- 

 stones or shades, which, though barren in themselves, are 

 valuable as affording a clue to the re-appearance of richer 

 deposits. These stones are partially rounded, and apparently 

 water-worn, and are found on the surface, or at very small 

 depths below it. Their mineralogical characters nearly 

 resemble those of the contents of the lodes or veins in the 

 vicinity, of which they are presumed to be fragments removed 

 by diluvial action. The proximity of veins is farther shown by 

 certain indications, which rarely fail to point out their near- 

 ness to the surface. These are, the barrenness of the spot, 

 the presence of shattered fragments of the stones above- 

 mentioned, and, occasionally, the harsh, metallic taste of the 

 water of some adjacent spring. Veins of copper are usually 

 found in connexion with an earthy, ochreous stone, locally 

 termed gossan, which is of a red colour, and crumbles like 

 the rust of iron. The peculiar substance called killas, which 

 has been described as a gneiss that has lost its schistose 

 character, and become comparatively easy and free to work, 

 affords another symptom of their occurrence. The lodes, or 

 veins', both of tin, copper, and other ores, exist most fre- 

 quently in the vicinity of granite, which is. called by the 

 miners their country. Metallic veins, also, usually occur 

 contiguous to axes of disturbance, and at points which 

 exhibit proofs of the action of fire. Since these circum- 

 stances are chiefly of local nature and origin, and" are 

 dependent on the character of the individual formation 

 to which they are referable, it will be seen that mineral 

 substances present themselves under such diversified con- 



