( 249 ) 

 "With the latter, generating mixtures of the 

 two earths fuch as they have been found 

 when analyfed. 



It muft, however, be ohferved, that not 

 unfrequently they have not an immediate 

 connexion with the calcareous carbonates ; 

 but are only found under them in the form 

 of globes and lenfes invefted externally with 

 that light grey crufi: which is obfervable in 

 a multitude of other flints. It is very pof- 

 fible that the produdion of thefe globes and 

 lenfes may be pofterior, and caufed by fil- 

 tration, after the formation of the calcareous 

 flrata. 



I fhall fay nothing of other quarries of 

 lime-ftone fituated in other parts of the 

 Euganean mountains, nor of the flints they 

 contain, as they do not eflentially differ 

 from the quarry above defcribed. 



But to return to the ftones which derive 

 their origin from lire, I fhall now proceed 

 to fpeak of a kind of lava, the molt noble 



and 



