442 ON THE GEOLOGY OF THE 



mit of that mountain, it has exactly the appearance of having 

 once formed a continuous bank, through which the torrents 

 have cut their way, and produced the numerous beautiful and 

 picturesque valleys which intersect it in all directions. Of these, 

 the Var itself may be considered as one ; and near its banks, 

 I have seen cliffs cut in this gravel of at least 400 feet high, and 

 quite perpendicular. The operations of the various little streams 

 which occupy the water-courses in wet weather, — for in dry 

 weather there is little or no water to be seen in them, — are 

 very remarkable : sometimes I have followed them up, having 

 barely room to squeeze myself through between the perpendi- 

 cular walls, and found the cut suddenly terminate in a circular 

 aperture, like a deep well, into which a little stream precipi- 

 tated itself. In the Vallon Obscur, the opening is in some 

 places not more than three to four feet, and the walls rise to 

 at least 100 feet on each side, fringed at top with shrubs and 

 trees, often hanging in frightful suspence overhead. Although 

 there be no regular beds, the general inclination of the gravel 

 towards the sea, is sufficiently distinct in every cut which runs 

 in that direction ; while in those that are at right angles to it, 

 the gravel seems to be more horizontally disposed, shewing, 

 that by some uniform impulse, it had been carried forward in 

 one constant direction, in the same way as the Var, and other 

 mountain torrents, transport their contributions, and deposite 

 them in the ocean. 



Unpromising as those heaps of gravel were at first appear- 

 ance, they afforded another very important link in the chain 

 of facts which this country presents. In the different hills, the 

 pebbles are bedded in sand, which is more or less abundant. 

 Deposites of clay are also common ; sometimes they occur on- 

 ly in small seams, sometimes in thick extensive beds, of at 

 least 30 to 40 feet. The colour is either of a yellowish drab, 



or 



