( ^^6 ) 



CHAP. XX. 



DIGRESSION RELATIVE TO THE DIFFER- 

 ENT VOLCANIC PRODUCTIONS OF THE 

 EUGANEAN MOUNTAINS. 



Exciirfion made to the Euganean mountains^ 

 by the author^ during the vocations of 

 1789, in order to compare the produBs of 

 the volcanos he had vifited 'with thofe of 

 the mountains of Padua — Defcription of 

 different fpecimens colleBed by him in this 

 excurfton — Three kinds of lavas at Monte 

 Cajlello — Erratic petrofdices mingled with 

 them^ of uncertain origin — Lavas of MoU" 

 te del Dofiati^ fome with a petrofdiceous 

 hafe^ and others with a horn fl one -Proof 

 that one of thefe once formed currents — 

 The accumulated prifmatic columns of 

 Monte Roffo have not for their bafe the 

 granite^ but the porphyry — Monte Ortone 

 abounds in prifmatic lavas ^ but fuch as are 

 lefs charaElerifed in their coffiguration — 

 Lavas of Monte Merlo with a granitous 



bafe 



