68 ‘otice of Mr, Schooleraji’s View of 
We have already observed that large fragments are form- 
ed loose in the earth ; they sometimes weigh four or five 
unds ; we have such specimens from these mines; they are 
of a cubical form, and are surrounded, except where they 
have been broken, by an earthy incrustation. = 
- Itis observed, that the marly earth thrown out from the 
pits, enriches the ground, so that ina few years it is covered 
with a very rank growth of trees, vines, &c, and this is a 
regular characteristic of old diggings. Innumerable por- 
tions of radiated quartz, and sharp fragments of flinty stones 
‘e mixed with the clay, and form the first stratum of about 
Durtec » The next is of ared clay, and is four or 
five feet thick, and less mixed with similar siliceous sub- 
stances. Then comes a layer of gravel and rounded sili- 
ceous pebbles, about one foot thick, containing small portions 
of lead ore. The thickness of the bed of ore is generally a 
foot ; and the lumps of ore appear to have been rounded 
by attrition, like common gravel.‘ This is the character of 
what is called the gravel ore, and no spars are found accom- 
panying it. The greatest proportion of lead ore is, howey- 
er, found imbedded in, and accompanied by the sulphate of 
barytes, resting in a thick stratum of marly clay, bottomed 
an limestone rock.” ‘They invariably arrive atthe rock at — 
the depth of from fifteen’ to twenty, or sometimes thirty 
feet—a new process by boring and blasting is now necessa- 
ry, and most diggers abandon their pits rather than prose- 
be resumed where hitherto it has been a aandoned. It 
Ghani ohne ak. 1 eR ie, Ar a 
which, if ‘unoccu 
