THE COASTS OF SICILY. 79 



the cultivated region as far as the Piano del Lago. 

 These extraneous cones are like so many blow-holes, 

 through which the subterranean fires have made 

 their way at different epochs. The origin of the 

 greater number is lost in the darkness of pre-historic 

 ages, but all belong to the present geological epoch, 

 and appear to be exclusively formed of ashes and 

 scoriae. Most of these are scattered over the woody 

 region, raising far above the trees their summits, 

 which are either green or bare according as their 

 formation is of more or less ancient date. These 

 secondary volcanos diminish in proportion as we 

 ascend the mountain ; and a very small number only 

 are to be met with near the summit. 



The mode of distribution of these extraneous 

 cones is in complete accordance with the observa- 

 tions which have been made during the eruptions. 

 It is of rare occurrence to find that the great crater 

 is alone in a state of activity. In rising towards 

 the mouth of this gigantic furnace, the lava acts 

 upon the sides of the mountain precisely in the 

 same manner as a hydraulic press, and in general 

 the earth is broken and opened by the action of 

 this enormous force. The burning torrent escapes 

 through this opening at the same time that it carries 

 away with it gaseous emanations, and throws into 

 the air the debris of the soil, which, falling back 

 around the recent volcano, soon invests it with a 

 ne\v cone, the eternal monument of its transitory 

 existence. Of the eighty eruptions whose date 

 is more or less well attested, only twenty-two 

 are looked upon as belonging to the great crater. 



