280 MOUNTAIN SLIDES. 



The important provincial town of Yeleia, near Piacenza, where 

 many interesting antiquities have been discovered within a few 

 years, was buried by a vast land-slip, probably about the time of 

 Probus, but no historical record of the event has survived to us. 



On the 14th of February, 1855, the hiU of Belmonte, a little 

 below the parish of San Stefan o, in Tuscany, shd into the valley 

 of the Tiber, which consequently flooded the village to the depth 

 of fifty feet, and was finally drained off by a tunnel. The mass 

 of debris is stated to have been about 3,500 feet long, 1,000 

 wide, and not less than 600 high.* 



Occurrences of this sort have been so numerous in the Alps 

 and Apennines, that ahnost every ItaHan mountain commune has 

 its tradition, its record, or its still visible traces of a great land- 

 shp within its own limits. The old chroniclers contain frequent 

 notices of such calamities, and Giovanni Yillani even records the 

 destruction of fifty houses and the loss of many lives, by a shde 

 of what seems to have been a spur of the hill of San Giorgio in 

 the city of Florence, in the year 1284.f 



Deficiency and excess of moisture are almost equally prejudi- 

 cial to the stability of large masses of earth. During the extra- 

 ordinarily dry summer of 1881 the winding surface of the chain 

 of hills of which San Giorgio — a steep ridge ahnost overhanging 



lakes. Few people knew anything about this new lake tiU Professor Filopanti 

 gave an account of it in the Monitore di Bologna, after a visit which he 

 made to the place. Although the Professor has not been able to renew his 

 visit, he has taken means to become acquainted with the present condition of 

 the lakelet. He learns that its breadth and depth have considerably dimin- 

 ished, as might have been expected, on account of the quantity of earth and 

 stone continually carried into the lake by the rains, and still more by the ma- 

 terials brought down by the torrent from above. Probably the lake in ten or 

 twenty years, though much contracted, will still be recognizable ; but in 

 course of time geologists will scarcely be able to find its traces. However 

 this may be, the history of the little lake of Savena may well be regarded as 

 in miniature that of most of the lakes formed thousands of years ago, and 

 which are filled up only in the course of centuries. 



*BiANCHi, Appendix to the Italian translation of Mrs. Somerville's 

 Physical OeograpTiy, p. xxxvi. 



f Cronica di Giovanni Villani, lib. vii., cap. 97. For descriptions of 

 other slides in Italy, see same author, lib. xi., cap. 26 ; Fanfani, Antologia 

 Italiana, parte ii., p. 95 ; Giuliani, Linguaggio vivente della Toscana, 1865, 

 lettera, 63. 



