Page:Transactions of the Geological Society, 1st series, vol. 4.djvu/150

 descriptions. In the mine of Huel Peever, which is the object of this memoir, almost every species of interruption occurred to which the veins of Cornwall are liable; and so completely was the skill and experience of the miner baffled in the progress of its workings, that its tin vein having been heaved (to use a technical phrase) by other veins, it was not discovered again by the exertion of much labour and expense during a lapse of nearly forty years. It may perhaps serve to render more intelligible the following description of the remarkable circumstances attending the veins of Huel Peever, if we notice on the subject of veins in general that those of which the direction is north and south are rarely metalliferous; that the veins containing copper and tin run, with little exception, about east and west. Their downward direction is seldom quite vertical; there is however a species of vein having also an east and west direction which is never metalliferous, but consists generally of clay; this vein is for the most part found to take a course under-ground much less approaching the perpendicular than the metalliferous veins. This variation from the perpendicular in an east and west vein, whether it be towards the north or south, is called the underlie, and when its direction or dip is opposed to that of the metalliferous vein, it mostly, disturbs the direction of the latter. The east and west non-metalliferous veins either from their customary effect in respect to other veins, or from their generally quick underlie, or from both, have obtained the name of slides.

The mine called Huel Peever is situate in the parish of Redruth, about one mile and a half north-east of the town of the same name. Its veins, to the extent of their workings both in length and depth, were found to pass only through schist, occasionally of a micaceous appearance, but in many parts the mica not being perceptible, it assumed the character of argillaceous schist.