Dr. Be RGETL on ibe Isle of Man. 53 



The walls of the vein are formed of silky grey wacke with pieces 

 of bitter spath, and a few flesh-red and lamellar crystals of calc spar. 



Fox dale Alines, 



The specific gravity of a rather impure specimen of lead-ore, I 

 found 6.095. 



Amongst the stony substances that fill up the vein, I remarked 

 the following varieties. 



A semitransparent and bluish ealcedony passing to v^^hite ; It is 

 zoned, but the zones are not apparent without the assistance of a 

 magnifying glass ; common galena and some iron pyrites are dis- 

 seminated throughout the mass. 



Sometimes the ealcedony verges into white quartz, blended with 

 sparry iron-ore scarcely effervescent with nitric acid, turning almost 

 black before the blowpipe and acting very powerfully on the mag- 

 net. It is likewise accompanied by iron-pyrites. 



The sparry iron-ore in larger lamellar crystals appears of a dark, 

 colour, and contains so much of iron as to act by itself on the 

 magnet. Galena adheres to it. 



The greywacke that forms the South side or cbeek of the vein, 

 is of a greyish colour with a silky lustre ; the common lead-ore 

 adheres to It. In a granular and drusy quartz filling up the vein, 

 I noticed a few garnets. 



Brada-head Mines. 



The specific gravity of a less Impure specimen of lead-ore than 

 that of Foxdalc, was 6,622. 



The principal vein-stone through which the ore is disseminated,., 

 is a yellowish granular quartz that includes iron pyrites. 



