140 Mr. Williams's account of the 



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 liabie ; 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-metal- 

 liferous 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. 



