( 252 ) 



pkch-ftones. This lava contains unequally 

 diftributed feltfpars of a flat form, friable, 

 and not very brilliant. Every flroke with 

 the fleel breaks off fome pieces, but extracts 

 no fparks. 



A few hours in the furnace deprive this 

 ftone of its colours, rendering it of an afh 

 grey : it likev^ife lofes its friability and 

 foftnefs, and becomes capable of giving 

 fparks with fteel ; refembling then a pafte 

 of porcelain. Continuing the heat longer, 

 the cinereous colour remains, with the ap- 

 pearance of very numerous bubbles ; and 

 the lava pafles into a homogeneous veficu- 

 lar enamel, with a fufion of the feltfpars. 



The fmall valley of Bajamonte is not, 

 however, the only place in which this 

 pitch-ftone lava is found ; it is met with 

 in feveral others ; as at Monte Sieva, and 

 its environs. We there find banks or 

 veins inclined in different angles to the 

 horizon, and fometimes perpendicular to it. 

 The lava of one of thefe has exadly the 

 £ colour 



