containing blende, calamine, andfmallquan-
titi'es of lead ore, with barytes, calcareous
fpar, and fluors. Here are feveral fhafts of
no great depth. In the vicinity are feveral
mafies of limeftone, conliftingof fmall pieces,
or angular fragments, cemented by the water
filtering through the mafs, and precipitating
its earthy particles, which conftitute a fta**
laditic matter pervading the interfaces.
SECT TOM'
S E C T I O N IX,
O f the Lead Ores.
T HOUGH lead ores generally contain
filver, none in Derbylhire, yet analyfed,
yield any portion qf that precious metal, fuf-
ficient to defray the expences neceflarily
attendant on the feparation of it.
The mo ft common lead ore is galena,
or fulphuret of lead, which generally lies
in larger or finaller veins and mafies ; frequently
in nodules, with cawk, a name
here ufed for barytes. Galena is frequently
çryftallized in cubes, with the angles truncated,
alfo in the odaedron and its modifications.
It is of a bright luftre,, and flaky
h 3 fradure.