128 THE DESERT OF EROSION. 



tary post, called Les Tamarins, the road descends the ravine-cloven 

 mountain-slopes, and passes over the torrent which bifurcates at the 

 foot of the majestic Metlili. On the left is seen a steep wall of rock, 

 the Jebel-Gaouss, cleft midway by a chasm, or breach, which the Arabs 

 expressively designate " The Mouth of the Desert," and which, 

 gradually enlarging, opens upon the first oasis of the Sahara, El 

 Kantara (" the bridge," from a Roman arch which spans the torrent), 

 the most northerly limit of the palm-tree. " A magnificent, semi- 

 alpine, semi-tropical scene. Below, a tumultuous foaming stream, its 

 banks on either side clad with palms bending their feathery foliage 

 towards the river, and sheltering fig, apricot, peach, almond, and 

 pomegranate trees."* Above, a range of snowy heights, wreathed in 

 ever ascending and descending clouds. 



We now enter the Desert of Erosion, a mass of mountainous high- 

 lands ; of ridges, peaks, and cols, intersected and, as it were, gashed 

 by ravines where roll the winter torrents and the rivers which the 

 heats of summer dry up, and which, hollowing and gnawing into the 

 stony soil, spread themselves over the valleys and awake a transitory 

 vegetation. The erosive action of the waters is, then, the special charac- 

 teristic of this part of the desert, which the Arabs call Kifar, or " the 

 abandoned country." Most of .the streams which water it have their 

 sources in Mounts Aures and Zibans, which form its northern boun- 

 dary. They have excavated wide intermingling furrows, whose inter- 

 vening spaces are occupied by gypseous plateaux. The formations of 

 less resisting power, the marls, clays, and sands, have been washed 

 away. 



The waters, whether proceeding from rain, or the melting of the 

 snows on the loftiest peaks, are very pure at first, and roll in deep 

 beds with vertical sides ; when they reach the plains, their channels 

 grow wider and shallower. In the wet season, the floods burst the 

 banks, and overflowing, carry down immense quantities of rolled 

 pebbles, which are distributed over an extensive area ; in ordinary 

 weather they are reduced to thin threads of silver, which, on arriving 

 * Tristram, " The Great Sahara," p. 354. 



