STATEMENT BY M. COSTA DE BASTELICA.. 247 



appearance of the woods. When one goes over these lands — cut into 

 ravines and despoiled of all vegetation — ^he meets with numerous 

 stumps of pine and of larch, which testify that at a period as yet stiU 

 recent they were covered by vast forests. 



" M. Surell cites, as an example of the action of forests, the torrent 

 of Savines, now completely extinguished, and the basin of which is 

 everywhere adorned with a magnificent forest of firs and pines. The 

 forest has effectively contributed to the extinction of the torrent, but 

 at this point the following observations may be made : 



" This natural extinction of the torrent goes back to ages most 

 remote. The cone is of a perfect geometric regularity. At its base, 

 opposite the Durance, it presents a troncature or section, produced by 

 the erosion of the river, and the escarpment of which is about 30 

 metres (100 feet) in height at its culminating point. This section 

 of the ground lays open the interior of the torrential deposit formed 

 of roUed pebbles. 



" The whole surface of the cone is cultivated, and on one portion 

 has been built the large village of Savines, the chief place of the 

 canton. 



" This enormous heap of deposit is situated at the foot of a high 

 mountain called Morgon, in the flanks of which are dug out a pro- 

 found gorge surrounded by a vast basin, the work of the water. All 

 the upper slopes of the mountain are hung with a beautiful forest, 

 producing firs more than 30 mfetres (100 feet) in height, and 3 metres 

 (10 feet) in girth. 



The lower slopes are deeply ravined, but wooded to the very edge 

 of the thalwegs. A pretty strong stream rises from the principal gorge, 

 but it swells but little ; it carries down no material, and it (lows into 

 the Durance by a bed deeply enclosed in the left bank of the cone. 

 Extinction and stability are complete ; but it is certain that if the 

 forest should be made to disappear, anew would disorder revive, and 

 this with the same intensity as before. 



" In going over the basin with attention, I satisfied myself that 

 everywhere the bed of the thalwegs of the gorges and the ravines, 

 formed of the hard rock, were absolutely incapable of being under- 

 mined. From this it may be inferred, that during the activity of the 

 torrent, when the basin was being deepened, more and more, the sur- 

 face could not have been wooded. But from the time that the waters 

 had everywhere reached the hard rock, and that they could no more 

 be undermined and washed deeper, their thalwegs in the upper slopes 

 tended to consolidate themselves, taking their natural stable declivity ; 



