96 NEWER PLIOCENE PERIOD. 



[Ch. VIII. 



It is recorded, as we have already seen in our history of 

 earthquakes, that in the year 1772 an immense subsidence took 

 place on Papandayang, the largest volcano in the island of 

 Java, and that, during the catastrophe, an extent of ground, 

 fifteen miles in length and six in breadth, gave way, so that no 

 less than forty villages were engulphed, and the cone lost no 

 less than four thousand feet of its height*. 



Now we might imagine a similar event, or a series of sub- 

 sidences to have formerly occurred on the eastern side of Etna, 

 although such catastrophes have not been witnessed in modern 

 times, or only on a very trifling scale. A narrow ravine, about 

 a mile long, twenty feet wide, and from twenty to thirty-six in 

 depth, has been formed, within the historical era, on the flanks 

 of the volcano, near the town of Mascalucia ; and a small cir- 

 cular tract, called the Cisterna, near the summit, sank down in 

 the year 1792, to the depth of about forty feet, and left on all 

 sides of the chasm a vertical section of the beds, exactly resem- 

 bling those which are seen in the precipices of the Val del 

 Bove. At some remote periods, therefore, we might suppose 

 more extensive portions of the mountain to have fallen in during 

 great earthquakes. 



But some geologists will, perhaps, incline to the opinion, 

 that the removed mass was blown up by paroxysmal explo- 

 sions, such as that which, in the year 79, destroyed the ancient 

 cone of Vesuvius, and gave rise to the escarpment of Somma. 

 The Val del Bove, it will be remembered, lies within the zone 

 of lateral eruptions, so that a repetition of volcanic explosions 

 might have taken place, after which the action of running 

 water may have contributed powerfully to degrade the rocks, 

 and to transport the materials to the sea. We have before 

 alluded to the effects of a violent flood, which swept through 

 the Val del Bove in the year 1755, when a fiery torrent of lava 

 had suddenly overflowed a great depth of snow in winter f. 



In the present imperfect state of our knowledge of the his- 



* Vol. i. chap. xxv. 

 t See vol. i. chap. xxi. 



