Scotland, from which I fhall.beg leave to
feled the mod eflential paffages on this
fubjed; particularly thofe pages where he
informs the reader that galena has been
worked in the toadftone ftratum.
Fagus de St, Fond, p. 328, fays, 4 Toad-
4 ftone containing lead ore, Mr. Whitehurft,
4 and Mr. Ferber affirm, that in all the mines
4 which have yet been opened, the vein of
4 ore is found exclufively in the limeftone,*
4 and difappears fo completely on reaching
4 the bed of toadftone, that not the fmalleft
4 veftige of it is difcoverable in the latter;
4 but that on piercing through the toadftone,
4 however thick, the vein as certainly makes
4 its reappearance; and this fad, they affirm^
4 holds good through every vein of ftrata,
4 to any depth. This difpofttion, however
* This is not exactly correct, as before ftated in this
work. It will be found that the lead ore is frequent in the
fhiftus, and fometiaies in the coal. >
4 aftonifhing,
4 aftonifhing, is in general true ; and thence
4 Mr. Whitehurft conceived the opinion
4 that the toadftone which thus feparatesthe
4 calcareous ftrata, and interrupts the courfe
4 of the ore, muft be the refult of different
4 currents of lava. My thoughts on this
4 fubjed have been already explained, but
t jf there fhould remain any doubt that the
4 toadftone is not a produd of volcanic fire,
4 the fad which X am now going to ftate
4 will be fufficient to remove them.
4 Dodor Pearfon having fpokento me,
4 at Caftleton, of a miner who fold feled
4 fpecimens for the cabinet, we went to pay
4 him a vifit. I purchafed from him a col-
4 ledion of the moft interefting minerals of
4 Derbyfhire, and fome fine pieces of fluor
4 fpar, the cryftals of which were in the
4 moft perfed prefervation.
4 In the courfe of converfation with him,
«l ^fked whether it was true that no vein
4 of