Page:Transactions of the Geological Society, 1st series, vol. 2.djvu/168

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Mr. William Phillips on the Veins of Cornwall.

profitable copper mines that Cornwall has now to boast of, a particular description of some of its veins would not have been now attempted, but for some circumstances worthy of particular notice, viz. that one of its veins is of that description termed a contre, remarkable for its magnitude and riches as well as its direction, and on account of the effects produced by its traversing an east to west vein, and a north and south vein, or cross course.

Both the shafts above alluded to were sunk on the contre, the direction of which is 28 degrees south of east and north of west. It varies from 9 to 24 feet in width, its underlie is 2 feet in a fathom to the east of north. At a small depth this bore the appellation of a ‘Flucany Load.’ Flucan prevailed very much between the depth of 50 and 70 fathoms from the surface, and burst out occasionally with such vehemence as to drive away the workmen. Captain Samuel Grose, an intelligent captain of the mine, informed me that he was once carried away 7 fathoms by its sudden irruption. But little flucan was seen at much greater depth. Beneath it and above the copper very great abundance of sulphuret and carbonate of lead occurred, together with iron pyrites, blende and quartz. The greatest extent to which the contre has been worked is 160 fathoms from its junction with the east and west vein towards the south east; 90 fathoms of which, at about 130 from the surface, are good ore. The only place at which the contre was rich when in contact with the east and west vein, was at about 117 fathoms from the surface. North-west of its junction with that vein the contre was small, and for more than 100 fathoms in depth consisted of strings of flucan, but at about the depth of 120 fathoms it enlarged to twelve feet in width and yielded some ore, mingled with fluor, blende, and iron pyrites in abundance; at 130 fathoms in depth, it was poor for 20 fathoms