ITALY. LETTER XVII. 24! 



undetermined polygone forms. However, there ap- 

 pear in the mafs of the rock fome diftincl: hexagonal- 

 quadrangular and triangular large bafalt-colonnes 

 and truncated mafies of them, obliquely peeping 

 from under ground. Hence may be juftly con- 

 cluded, that the whole mafs of lava, which com- 

 pofes this hill, had a general tendency to cryftal- 

 lize into prifms, but that its prefiure and quan- 

 tity did not permit every where an equal and dif- 

 tincT: cryftallization. In fome prifms of this lava 

 are inclofed fragments of white limeftone ; fuch 

 as I have noticed with the lavas of Vefuvius and 

 monte Albano. No volcanic afhes, but marl, is to 

 be feen all around this huge lava-lump , I could 

 not difcover any mark of a former volcanic crater 

 or funnel, though there be, hereabout, a tradi- 

 tional faying of its former eruptions. I conjec- 

 ture, therefore, that the funnel was in the valley, 

 and has been covered by marl. Directly above 

 Radicofani, on the other fide of the valley, rifes 

 a higher lava-hill, called S. Ficre-, which may 

 have had, perhaps, in the finking plain of its fum- 

 mit, an ancient volcanic funnel * : however, it is 



more 



* This mountain called Montagna ammiata, or di S. Fior? t 

 or Santa Fiora, confifts on one fide in lavas and volcanic ma- 

 terials ; but on the other, which I did not fee, it is calcareous 

 according to Mr. Tergioni Tox.ztitfs authority. J faw in hi* 

 R . coiie&ious 



