140 



Depth of the 

 ftraU. 



Pefcent Into 

 jChem* 



The roof fup- 

 ported by wails 

 and timber. 



The ftones fe- 

 parated by iron 

 » edges. 

 The ihafts nu- 

 merous , and 

 very dangerous 

 from being left 

 open. 



Thefe quarries 

 wrought for fc- 

 veral centuries. 



Its crater pro- 

 bably at mount 

 Blemberg. 

 Beyond Meder- 

 n cnich a bed 

 of the fame lava, 

 with a perpendi- 

 cular face, form- 

 ing a ravine 

 a 5 feet deep, and 

 covered with a 

 thin ftratum of 

 mould. 

 This too 

 wriought, and 

 theftone harder 

 from its expo- 

 fure to the air. 

 Beyond this, and 

 fo me lava of 

 the piperino 

 fpecies, is a 

 cold acidulous 

 chalybeate 

 fpring. 

 More lava in 

 which were for- 

 metly ^uarrics» 



ON KXTINCT VGtCANOJiS. 



for which there is a very great demand. Thefe quarries ar« 

 underground, and in thefe are fliafts a hundred feet deep, to 

 facilitate the working. 



The firil ftratum was mould, about 15 feet thick. 



The fecond, fcorix of lava, about 12 



Total 27. 



Beneath was the pure and compaft lava. The defcent into 

 thefe quarries is by a flair of 120 fteps, and a gentle defcent 

 of near 90 paces. The fragments of the ftones got out ferved 

 to make internal walls of fupport, to which were added ftan- 

 chions of timber, in fome places perpendicular, in others ob- 

 lique, but always contrived to fupport the blocks feparated by 

 filfures. The ftones were broken off* by iron wedges, for they 

 were afraid to feparate them by blafting. 



I counted eighteen or twenty fhafts in the fpace I traverfed ; 

 and their mouths being perfedly open, woe to the traveller 

 who fliould lofe his way among them by night. I obferved fe- 

 veral of them covered up, indicating works abandoned ; 

 whence we may prefume, that thefe quarries had been wrought 

 for feveral centuries. Some old oaks likewife growing in the 

 fhafts thus covered confirm this opini®n. 



The thicknefs of the ftrata covering this lava prevented me 

 from following its courfe, and tracing it to its fource; but I 

 judged, that the mountain of Blemberg, a league to the fouth- 

 weft, might be its crater. Accordingly I proceeded to ex- 

 amine it. A quarter of a league from Medermenich I found a 

 bed of the fame lava, the face of which was perpendicular, 

 and forming a gully, that might be twenty-five feet deep. It 

 is covered by a very thin ftratum of mould, and is wrought 

 into inillftones, and ftones for building. Being expofed to the 

 open air, it is harder than that of Medermenich. 



After having palTed this gully, and a little bed of muddy 

 lava, of the nature of piperino, we find in a meadow a very 

 copious mineral fpring. It is cold, and contains carbonic acid 

 and iron. At fome diftance from this we meet with beds of 

 lava, in which there had anciently been feveral quarries, and 

 at length we arrive at the mountains of Blemberg. The furr 

 face of this mountain, though covered with trees on the eaft, 

 is neverthelefs full of torrefied and fcorified lava, and gray and 

 red pouzzolona, which left me no doubt, that this mountain 

 h^d formerly been a volcano. Th? infpe^ion of its fumralt 



