of Devonshire and ConnvaU, 163 



D. Of the Course of the Veins in Cornwall. 



Almost all the veins in this country, as well as those in Devonshire, 

 belong to the class of oblique or inclined veins. Their degree of in- 

 clination varies, but according to the information I received on the 

 ' spot, and from what 1 saw myself, I believe, that taking an average, 

 they may be said to dip a foot and a half in each fathom. The point 

 of the compass to which they dip varies. Some mineralogists think 

 that the veins of copper generally dip to the north, and those of 

 tin to the south : but we must look to practical miners for the most 

 accurate information on this head.* 



The position or direction of the productive veins is from cast to 

 west, or more correctly from E.S.E. to W.N.W. forming what used 

 to be called in France flons du matin. \ It is remarkable that in 

 England, and also in Scotland, all veins of whatsoever age, or of 

 whatsoever ore they may be composed, have nearly the same 

 position, which would seem to indicate, that the cause to which they 

 owe their existence, had acted in the same direction, though at dif- 

 ferent periods. It appears then that the veins run parallel to each 

 other. The tin veins are not so long as those of copper, and they 



that which is found in the bed of the river Dee in Aberdeenshire, and M. Cordicr has 

 analysed a great variety of different kinds gathered in volcanic countries. Journal 

 des Mines, No. 124. 



* Metallic veins in Derbyshire near Castlcton, run from cast to west, and are traced or 

 discovered from the surface. They incline about one foot in ten, sometimes to the north, 

 Bomctimes to the south. Mawe's Mineralogy of Derbyshire, p. 2. 



+ In Brittany, on the contrary, they consider as barren, all the veins which have a 

 direction from east to west ; the best run nearly from north to south, or at least do not 

 Tary much from that direction. Journal des Mines, No. xvi. 



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