113 



A singular discovery of a lump of Stibnite in the Glacial drift 

 near Troutbeck Station (Cockermouth, Keswick, and Penrith 

 Railway), is mentioned in Ward's Geology of the Northern Part of 

 the Lake District. 



BisMUTHiNE, Bismuth Glance, or Bismuth tersulphide, is 

 another ore of Bismuth found at Brandy Gill. Our specimens 

 have the aspect of dull, greasy-looking, lead-coloured scales, with 

 somewhat more lustre than that of lead. They occur chiefly in the 

 quartz vein-stuff along with the minerals already enumerated from 

 the same locality. The British Museum specimens are almost 

 certainly from the Brandy Gill locality. 



MisPiCKEL, Iron Arseno-Sulphide, has already been mentioned 

 as occurring along with Molybdenite at Brandy Gill. It occurs as 

 granular steely-looking masses in the interstices between the faces 

 of the quartz crystals in the vein-stuff; and is generally remarkable 

 for the pecuHar tarnish developed on the surface of the mineral 

 after some exposure to the weather. Much of the quartz around 

 the Mispickel is often stained, or coated, with a ferruginous deposit, 

 probably due to the partial decomposition of the ore. 



Another ore of copper of considerable importance in some 

 districts is Fahlerz, Fahlore, Grey Copper ore, Tetrahedrite, the 

 Tetra-basic Sulph-Antimonide of Copper. 



This occurs at only two localities that I am aware of, and these 

 are in the veins traversing the disturbed mass of Mountain Lime- 

 stone adjoining the Great Pennine Faults at Clouds, to the south 

 of Kirkby Stephen; and, in smaller quantities, under the same 

 circumstances to the east of Harcla, Kirkby Stephen. The ore 

 occurs in the form of irregular lumps of a grey colour, with a 

 sub-metallic lustre on the freshly-fractured surface ; but exteriorly 

 more or less tinged with an ochreous rust due to the oxidation of 

 part of its iron. The interior of each lump is frequently occupied 

 by irregular cavities lined with the blue and the green carbonates 

 of copper; while traces of Chalcopyrites maybe detected here 

 and there in the solid parts of the ore. It is associated with 



