yS JS'^otice of Mr, SchoolcrafVs Flew of 



We have already observed that large fragments are form- 

 ed loose in the earth ; they sometimes vvei^gh four or five 

 pounds ; 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. 



It is observed, that the marly earth thrown out from the 

 pits, enriches the ground, so that in a 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 

 are mixed with the clay, and form the first stratum of about 

 fourteen inches. The next is of a red 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, howev- 

 er, found imbedded in, and accompanied by the sulphate of 

 barytes, resting in a thick stratum of marly clay, bottomed 

 on limestone rock." They invariably arrive at the 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- 

 cute them at this expense. If, however, (as there can be 

 little doubt,) the limestone is the real matrix of the lead ore, 

 the time will come when the present diggings will be con- 

 sidered as merely superficial beginnings, and the work will 

 be resumed where hitherto it has been abandoned. It 

 seems that the almost invariable practice of the miners now 

 is, to persevere till they strike the rock, and then to go and 

 dig elsewhere ; they cannot, if disposed, prosecute the busi- 

 ness by levels or galleries, for they are not permitted to car- 

 ry on their mining, except immediately under the surface 

 that is covered by their respective leases, or by twelve feet 

 square which, if unoccupied, an adventurer may cover by 

 occupancy. Among the substances accompanying the lead, 

 blende and the sulphate of barytes, are said to be very 

 abundant*, the latter in specimens which we have, is par- 



