THE COASTS OF SICILY. 115 



the slightest irregularity, is continued both above and 

 below the point at which the liquid matter found 

 vent ; and, however numerous these veins may be, 

 the strata are never thicker in the base of the valley 

 than at the level of the Serre del Solfizio. It follows 

 from hence that if, at the epoch of the formation of 

 these strata, the soil had presented the same inclina- 

 tion which it now exhibits, the lava, instead of flow- 

 ing in a mass towards the foot of the volcano, would 

 in part have ascended towards the summit, contrary 

 to the laws of gravity. All these facts admit, on the 

 other hand, of a very natural explanation on the sup- 

 position which we have already advanced, that at the 

 moment of the emission of this lava, the surface of 

 the soil was horizontal, and that consequently these 

 fused matters were able to distribute themselves 

 freely in all directions. 



We have hitherto only taken into account, in our 

 consideration of the walls of the Val del Bove, those 

 matters which formerly existed in a fluid condition. 

 An examination of the strata which have been 

 formed by ashes and scoriae, would however, lead to 

 the same result. If at the moment of their emission 

 these fragments, which have been thrown into the 

 air by a single mouth in the same manner as the 

 modern lapilli, had fallen back upon inclined planes 

 they would necessarily have comported themselves 

 in the same manner as a mass of sand and loose stones 

 falling down a flight of stairs. They would have 

 smoothed the irregularities of the incline by accu- 

 mulating upon the lesser slopes, and merely covering 

 the steeper declivities by a very thin stratum. This 



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