EXTINGUISHED TORRENTS. 
263 
at the present hour, depressing still lower the ridges of the 
Alps and the Apennines, raising still higher the plains of 
Lombardy and Provence, extending the coast still farther into 
the Adriatic and the Mediterranean, reducing the inclination 
of their own beds and the rapidity of their flow, and thus 
tending to become river-like in character. 
There are cases where torrents cease their ravages of them¬ 
selves, in consequence of some change in the condition of the 
•basin where they originate, or of the face of the mountain at a 
higher level, while the plain or the sea below remains in sub¬ 
stantially the same state as before. If a torrent rises in a 
small valley containing no great amount of earth and of disin¬ 
tegrated or loose rock, it may, in the course of a certain period, 
wash out all the transportable material, and if the valley is 
then left with solid walls, it will cease to furnish debris to be 
carried down by floods. If, in this state of things, a new 
channel be formed at an elevation above the head of the val¬ 
ley, it may divert a part, or even the whole of the rain water 
and melted snow which would otherwise have flowed into it, 
and the once furious torrent now sinks to the rank of a hum¬ 
ble and harmless brooklet. “ In traversing this department,” 
says Surell, a one often sees, at the outlet ot a gorge, a flat¬ 
tened hillock, with a fan-shaped outline and regular slopes ; it 
is the bed of dejection of an ancient torrent. It sometimes 
requires long and careful study to detect the primitive form, 
masked as it is by groves of trees, by cultivated fields, and 
often by houses, but, when examined closely, and from differ¬ 
ent points of view, its characteristic figure manifestly appears, 
and its true history cannot be mistaken. Along the hillock 
flows a streamlet, issuing from the ravine, and quietly watering 
the fields. This was originally a torrent, and in the back¬ 
ground may be discovered its mountain basin. Such extin¬ 
guished torrents, if I may use the expression, are numerous.” * 
* Surell, Les Torrents des Hautes Alpes , chap. xxiv. In such cases, 
the clearing of the ground, which, in consequence of a temporary diver¬ 
sion of the waters, or from some other cause, has become rewooded, some¬ 
times renews the ravages of the torrent. 3 hus, on the left bank of the 
