VOL. LXllI.] PHILOSOPHICAL TRANSACTIONS. 369 



were many different branches of the cavern ; tliey tied one ball of packthread to 

 another, as they went forward, that they might more easily lind their way back. 

 This branch is not so horizontal as the other ; it declines downwards, and the 

 openings in it are vastly wider, some being at least 100 yards wide, and above 

 50 high. A small rill accompanied them, which, by its different falls, formed 

 a sort of nide harmony, well suited to the place. In a standing part of this 

 brook, and near a quarter of a mile from the entrance, they found the bones of 

 a hundred at least of the human race; some were very large, but when taken 

 out of the water they crumbled away. As they could find nothing like an in- 

 scription, or earth for a burying place, they conjectured that some of the civil 

 wars, perhaps that of l64l, might have driven the owners of these bones into 

 this place. The tradition of the neighbourhood threw no light upon it. 



Many of the rocks, on the roof and sides of this cavern, are black marble, 

 full of white spots of a shell-like figure ; and the whole neighbourhood is full of 

 quarries of this beautiful stone, which takes a fine polish, and is used through 

 the three kingdoms for slabs, chimney pieces, &c. In some deep and wet parts 

 of these quarries, this elegant fossil is seen in the first stages of its formation; 

 the shells are real, but so softened by time and their moist situation, as to be 

 susceptible of receiving the stony particles into their pores, by whose cohesive 

 quality, they in time become those hard white curls that give value to the marble: 

 and it is very remarkable, and a proof that these white spots have been real shells, 

 and thus formed, that the longer a chimney piece or slab is used, the more of 

 those spots ripen into view. 



///. On some Specimens of Native Lead found in a Mine of Monmouthshire. By 

 Michael Morris, M.D., F.R.S. p. 20. 



About the middle of July 1772, Dr. M. received 3 specimens of lead ore from 

 Valentine Morris, Esq. of Piercefield in Monmouthshire. They were dug up 

 in one of his fields, on making some drains, at no considerable depth; they 

 were marked N° 1, 1, 3. On reducing to powder an ounce and a half of the 

 ore, marked N" 3, in order to assay it, he perceived that several small bits were 

 flatted by the pestle, which, on a further examination, proved to be native lead. 

 Though the bits of lead are inconsiderable, yet, as they are the first that have 

 been publicly seen in England, or perhaps in Europe, some of the best and latest 

 writers on mineralogy declaring that they have not met with any, he thought it 

 his duty to acquaint the r. s. with the fact, that the first account of native lead 

 may appear in the Phil. Trans., as well as the first account of native tin. 



VOL. xiir. 3 B 



