OMAIN XII. VOLCANIC. 



" Felsite lava of a grey white, fine paste, scaly y 

 and of a shining reflection, and satiny, of an ana- 

 logous nature to the preceding in respect to its 

 composition ; but differs in as much as the action 

 of volcanic fire has impressed on the paste a cha- 

 racter of fusion similar to that of pumice, while 

 the granular fragments of felspar, whiter and of a 

 more diaphanous nature, which are immersed in 

 the massive felspar, have more resisted the action 

 of fire, and remain nearly untouched. 



" Felsite lava of a deep Isabella colour, with 

 grains of white diaphanous felspar, and a number 

 of small specks of black mica, which have re- 

 mained untouched in the midst of the striated 

 base, rather porous, and passed into the state of 

 pumice. This felsite lava has relations with the 

 preceding ; but its contexture is more rough, and 

 its pores closer ; its aspect has an appearance of 

 pitchstone ; which obtained it, from Dolomieu> 

 the name of resin if or m lava. 



" Grey felsite lava, with a multitude of small 

 globules more or less round, and inherent in the 

 base, of a substance analogous to that of felspar, 

 of a deeper colour than the paste which contains 

 them, and in which they have been primitively 

 formed : their contexture is closer and rather 

 vitreous. This lava, which is hard, and suscep- 

 tible of being polished, appears spotted, and pre- 



