ITALY. LETTER XVII. 235 



white. 4. White hills of Piperino, or a mixture 

 of white afhes, black fmall fherl points, fome 

 glofly fherl-larnelles and inclofed fragments of 

 limeftorte, as in the Piperino at Marino, near A/. 

 Albano. This continued till mcnte Roft. The road 

 covered with black fherl-fand warned by rain. 

 Behind monte Rofi^ on the road to Ronciglione, a 

 lava-torrent ; and fomewhat further, a fmall lake, 

 Lago di monte Rqft, which feems to have been an 

 old volcano. Near P\.onciglione a deep beautiful 

 valley, ftretching through a high yellow-brown 

 tufo-hill, with many picturefque romantic views. 

 Followed a large lake, Lago di Vico, a funk crater 

 of an old volcano. La Montana di Viterbo is a 

 remaining part of its former circumference ; and 

 monte Vemre, in the lake, a part of its kernel or 

 nucleus, being of thi* fame fubftance as Moniagr.a 

 di Viterlo* This high mountain confifts of the 

 following materials, accumulated without any or- 

 der : 



a. Black compact lava, with plenty of vitreous 

 01 farinaceous greater and finaller Iherl-cryftals. 

 b. Decayed lava, at the ieaft touch mouldering 

 ii.ro a black-grey powder, with inclofed large 

 white garnet-like fherls likewife decayed, c. Beds 

 or torrents of compact black lava. d. Black-red 

 hardened pozzolana ', with e. red pumice-ftone. 

 /. Pitm'no, confilling in white-grey pnzzolana, 



mixed 



