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 inclination varies, but according to the information I received on the spot, and from what I 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.[1]
The position or direction of the productive veins is from east to west, or more correctly from E.S.E. to W.N.W. forming what used to be called in France filons du matin.[2] 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 different 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
- ↑ Metallic veins in Derbyshire near Castleton, run from east to west, and are traced or discovered from the surface. They incline about one foot in ten, sometimes to the north, sometimes 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 vary much from that direction. Journal des Mines, No. xvi.
