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name ; not only becaufe they are Integral 

 parts of this volcanic mountain, but becaufe 

 ihey appertain to a kind of ftones of the 

 Euganean hills, which, as will appear 

 from fads hereafter adduced, bear evident 

 marks of having fuffered fufion. 



In the midft of thefe lavas are found 

 pieces of petrofilex of a very fine grain, 

 which, as they are detached and fcattered, 

 I am unable to fay whether they have been 

 affedled by the fire, or thrown out un- 

 touched by fome volcano. All of them 

 contain cryftallizations of micas, flioerls, 

 and feitfpars ; and thefe cryftallizations 

 fufe in the furnace together with the petro- 

 filiceous bafe. 



From Monte-Caftello I proceeded to the 

 neighbouring mountain Donati. At the 

 top it has a double fummit ; and both there 

 and at the bafe, having broken off fevcral 

 pieces from the ftony mafs of the mountain, 

 it appeared to me that the lavas of which 

 it is compofed may be reduced to two 

 4 kinds 



