( 3^5 ) 



The produdts of the Euganean moun- 

 tains, we have i'een, are perfedly hmilar. 

 The bafe of their lavas, which is fhoerl, 

 feUfpar in the mafs, pitch-ftone, horn-ftone, 

 or petrofilex, Is combined whh feltfpar, 

 cryftalUzed fhoerl, or quartzofe grains. And 

 though I only examined a part of thefe 

 mountains, yet, from the more extenfive 

 obfervations of Sir J. Strange, we are au- 

 thorifed to fay that the nucleus of them 

 all is compofed of this ftone. It is there- 

 fore evident that the anciept fubterranean 

 lires, which have laid wafte a great part of 

 Italy and the adjacent countries, have had 

 their feat in thefe rocks ; and v/ho can fay- 

 to how imnienfe a depth they may have 

 extended beneath the furface of the earth ? 

 I fay beneath the furface, becaufe, though 

 by the violence of volcanic fires large and 

 numerous mafles arife above the lurface, 

 both on this and the other fide of the 

 Apennines, they never, or fcarcely ever, 

 concur to the formation of thefe, which 

 principally refult, as may be obferved in 

 many parts of them, from the calcareous 



VOL. III. X carbonates, 



