From the Desert of the Table-lands we must needs make another descent. The town of Batna is situated at the extremity of the lowest of the Atlantean terraces, whose elevation is still some 3300 feet above the level of the sea. To the north-west rise the lofty spires of the colossal chain, with their diadems of cedars sharply defined in black upon the azure of the sky. Loftiest of all soars the _Jebel-Tougour_, or "Peak of Cedars," reminding the spectator of the Pyrenean crests. Towards the south-east stretch the rounded shoulders of the mountains of the Aurès, clad with dense dark forest of oak and pine. In a fold of the mountains lurk the ancient Lambessa and the mouldering ruins of a Roman camp. Four miles to the south of Batna is a large depressed hill, whose base mingles with the table-land, above which it rises only three hundred and thirty feet. This ridge marks the watershed; all the streams on the north flowing towards the Mediterranean, and, on the south, gradually disappearing in the arid bed of the ancient Saharan sea. On the frontier line, like a Cyclopean landmark, is planted the Peak of Cedars, while from its loins a torrent issues, and through a deep ravine whirls and leaps and flows towards the desert. Springs, abundant and warm, bubble up through the chalky marls, and take the same direction. Beyond the French military 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."[55] Above, a range of snowy heights, wreathed in ever ascending and descending clouds.