ON MINERAL VEINS. ,'i83 



and nature of its contents. The extent of such dis- 

 locations in veins is variable; as might he inferred 

 from the motions of the disrupted strata, in which 

 they necessarily partake. These form an object of 

 the highest interest to the miner; and it is through 

 previous judgments respecting them, that he is taught 

 where to seek for the continuation of that which he 

 has lost. Experience in a given country often forms 

 a guide for these ; but rules so deduced cannot be ex- 

 tended to other countries, or to remote places. To 

 determine whether the motion of one part of an in- 

 clined vein is to be termed an elevation or a depres- 

 sion, it is necessary to take the point of departure 

 from the surface, as in the case of dislocated strata. 

 When a vertical vein is shifted, it is evident that the 

 adjacent rocks must all have been moved, by the same 

 quantity, in a horizontal direction; an event, as for- 

 merly remarked, not favourable to the theory which 

 supposes the fractures of strata to be the effect of 

 subsidence. The last circumstance relating to the 

 forms of veins, is their ramification. They are oc- 

 casionally separated, and again reunited ; certain tech- 

 nical terms being, in mining countries, applied to 

 the intermediate mass. In other cases, they send out 

 slender ramifications; and sometimes they are found 

 to ramify at once into many small branches. 



I have separated from that which is matter of jus- 

 tifiable inference respecting the ages of veins, what 

 can only be considered as an hypothesis, neither in- 

 telligible nor useful. It has been said, by that school 

 which has so long obstructed the progress of Geology, 

 that there are epochas in metallic veins, or that the 

 metals themselves are of different ages. Thus it is 

 said that Tin is among the oldest metals because it is 

 found in granite, and that lead is among the newest 



