6o4 On the Aerated Barytes. 



The Aerated Barytes near the furface does not 

 contain much Lead Ore, but when it is found in the 

 fecond ftratum of Sand-ftone, it forms the richeft 

 part of the mine. In the immediately following 

 ilratum of Shiver, it becomes more fcarce, and 

 indeed its prefence there is not looked upon as a 

 good omen, as it then contains large quantities of 

 Blende and Pyrites and but little Lead Ore. But 

 whatever the Matrix be, it is a general obfervation 

 that the vein is richer in paffing through the ftrata 

 of Sand-ftone, than through thofe of Shiver. 



The Ore is fometimes found in the form of a 

 regular vein, but more commonly in irregular 

 nodules or clufters, diffeminated throughout the 

 matrix. Where the vein is very thick, the greateft 

 part of it is ufually filled up with detached pieces 

 of Sand-ftone and Shiver, which is more particularly 

 the cafe where one vein runs into another. In 

 finking the Under-ground Shaft which I mentioned 

 before, the quantity of ore decreafed in proportion 

 to the depth, until at the depth of ten yards they 

 entirely loft it, the vein ftill continuing of the 

 fame thicknefs. The matrix was loofe vitriolated 

 Barytes. They were endeavouring to regain the 

 Ore and had applied a fmall pump, worked by a 

 water wheel in the valley above, to raife the water 

 to the level, called South Level, which carries off all 

 thofe of the mine. 



It appears from the beft of my information that 

 this Mine was firft worked about a century ago; it 



was 



