sxii P R E.FA.C E- 



:,!i -J \ U 



flate, nature, fituation, ground, principles, 

 and connection with other foffils. Of courfq 

 they left us in the dark on all thefe fubjects; 

 told us many a pretty tale of marcafite, bi- 

 tumen, and precious flones; and were fair 

 game for the fubtle lava-dealers at Naples, 

 who, like their kindred Italian antiquity- 

 fellers, cannot be fuppofed to be remarkably - 

 confcientious, I have feen dear-bought 

 pretended Vefuvian precious ftones, which, 

 upon nearer examination, were found to be 

 artinciarglaffes ; and fome tables, inlaid with 

 pretended Vefuvian and Sicilian lavas ? which, 

 for the greater part, were extremely apocry- 

 phal, or confided of marbles. 



Mr. 'Defmare/tj an eminent mineralogift, 

 who was employed for fome time to examine 

 the natural productions of France, obferved 

 that fome mafies of prifmatical bafakes in 

 Auvergne are immediately connected with the 

 larva's "and other volcanic foflils of that coun- 

 try -/and, being in their fubftance and colour 

 lb.~ nearly related to them, he ventured in 

 1768 the hypothecs, " that this fort of 



<' ftonc is belonging to, and produced by, 





