Page:Transactions of the Geological Society, 1st series, vol. 2.djvu/135

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125
Mr. William Phillips on the Veins of Cornwall.

try the second, that he has at least a good chance of meeting with all the veins between the extremity of the adit and the vein to which he intends to drive it. Yet of this he is not altogether certain, for the east and west vein is sometimes so greatly disordered by the cross vein, as that it might wholly escape the notice of the miner; besides, cross veins often divide into branches, so that the miner runs the hazard of following the wrong branch, and thereby of missing altogether the metalliferous vein. But although the mode of discovering veins, by driving an adit along the run of a cross course is at once the cheapest and most expeditious method, it is not always practised, as the foresight of the experienced miner sometimes induces him rather to drive through the solid country than to hazard the chance of being obliged to draw the water of the country all around him, which he is aware the cross vein would prevent from troubling him on one side.

Accident often occasions the discovery of veins. That of the mine called Huel Maggot, or Velenoweth in the parish of Phillack, was first seen by workmen employed in digging a trench for the foundation of a garden wall in a valley. It there consisted of a rich gossan, which in the phrase of the miner was very kindly. On driving into the hill, a few fathoms on the ‘course of the load,’ it produced abundance of sulphat of lead in well defined crystals, sometimes accompanied by the sulphuret, and sometimes deposited on the gossan, and, a little deeper, copper ore in considerable quantity. Both were however soon exhausted, and the mine was abandoned. The run or course of an east and west vein may sometimes be traced on the surface, by loose fragments or portions of earthy or stony substances, having generally more or less of an ochreous tinge, but this, which is called the ‘bryle of the load,’ has rarely a regular separation from the country on each side of it. But in sinking a