380 ON MINERAL VEINS. 



of the metals is in distant veins. Manganese also 

 occurs in the form of beds, as has been said to happen 

 with repect to mercury, copper, lead, and silver ; but 

 it must be remembered that veins holding a course 

 parallel to the including strata, have sometimes been 

 mistaken for beds. I suppress the provincial terms, 

 flat veins and rake veins, as I have avoided those on 

 all other occasions, siri*ce no useful information is 

 communicated by this practice, which also incumbers 

 geology still further with terms, and corrupts the En- 

 glish tongue. To shroud in the mystic phraseology of 

 an art, that which can be expressed in ordinary lan- 

 guage, is the result of a poor ambition, or a proof of 

 the superiority of the memory to the understanding. 



Of the Forms, Positions, and Relations of Mineral 



Veins. 



Mineral, like rock veins, intersect the strata at all 

 angles, and are also occasionally parallel to them 

 throughout more or less of their courses. They 

 imply a discontinuity of the rocks through which they 

 pass, being composed of matter which has entered 

 into the fissures formerly described in treating of the 

 positions of strata ; and hence they are occasionally 

 accompanied by dislocations of the including strata. 

 As they may hold any direction with regard to those, 

 so they may be placed in any position towards the 

 horizon ; though, from a mere comparison of chances, 

 it is plain that they must be far more frequently 

 inclined than vertical. Hence miners distinguish 

 between the upper and under sides of a vein. When 

 mineral veins occur in considerable numbers in any 

 tract of country, they maintain a sort of general paral- 

 lelism ; as if all the fissures to which they owe their 

 origin had been formed at the same time by some. 



