no 



point to the deposition of the ore having been the result of an 

 extremely complex, and delicately-adjusted, series of causes 

 variously combining to reduce the temperature of the mineral 

 solutions that were rising through the deeper-seated fissures until 

 the depositing point was reached. This must have taken place 

 during a period of a^-heaval, because the evidence often clearly 

 shews that the walls of the vein were repeatedly stretched asunder 

 during the formation of the mineral vein ; thereby shewing that the 

 rocks were being subjected to lateral tension as the rocks adjusted 

 themselves from a smaller horizontal extension to a larger during 

 their last upheaval. 



Another sulphide of some importance is Chalcopyrite, Copper 

 Pyrites, or "Yellow Ore" — a double Sulphide of Copper and 

 Iron. The principal mines of Copper Pyrites in this district 

 are in the neighbourhood of Keswick and of the Caldbeck 

 Fells. On the south side of the Lake District, there are 

 the well known mines at Coniston, and here and there, chiefly 

 amongst the Cambrian and the Silurian rocks of the Lake District 

 isolated mines of more or less importance have been worked. 

 Copper in the same form has been wrought in the Carboniferous 

 Limestone of the upper parts of Edenside at Clouds Mine, and in 

 Mallerstang ; and again close to Harcla, near Kirkby Stephen ; 

 and traces of the same ore occur about Helton, where the vein 

 stuff consists of quartz. 



The ore usually occurs in the form of interrupted strings and 

 irregular masses varying greatly in form and size, and traversing 

 the vein stuff, which is most commonly quartz, in much the same 

 way that galena does. Crystalline forms are not commonly met 

 with. The general aspect of the ore occurring with us is that of 

 metallic-looking masses more or less of the colour of gold, but with 

 a marked disposition to assume a tarnished surface. Copper pyrites 

 cannot be hammered out in the way that gold can, and it is further 

 distinguished from the only other mineral that bears any superficial 

 resemblance to it — Pyrites — by its inferior hardness. The ore of 

 copper can be cut with a knife, whereas Pyrites is sufficiently hard 

 to strike fire with steel. 



