NOME VIII. VOLCANIC GLUTfcNITE. 



silky threads of unequal length, united in fasces, 

 with diverging rays ; but the chief singularity is, 

 that all the mass is full of petrol, which also fills 

 many of the cavities. On breaking this lava the 

 oil runs out, which, though of a black colour, is 

 so subtile as to approach naphtha, with a pungent 

 smell, which it soon loses in the air. There seems 

 no reason to doubt that this petrol has been pro- 

 duced by infiltration *." 



HYPONOME III. INDURATED MUD WITH FELSPAR, SI- 

 DERITE, &C. 



NOME VIII. VOLCANIC GLUTENITE. 



This denomination includes, as usual, what 

 are called bricias and pudding-stones, being 

 fragments of different rocks joined by lava or 

 tufo. The peperino of the Italians is a volcanic p epe rino, 

 bricia ; the cement being a grey pumaceous 

 tufo, in which are concreted fragments of gra- 

 nite, felsite, marble, gypsum, with crystals of 

 siderite and mica. In the extinct volcano of 

 Beaulieu, three leagues to the N. W. of Aix in 

 Provence, Saussure observed a singular pud- 

 ding-stone, composed of fragments of vesicular 



* Ferrara, 179. 



