Several of these flat-topped precipitous heights have frequently served as a refuge for whole tribes and their flocks. Such, north-east of Tebessa, is the Kalaa-es-Senam, or "Castle of Idols," 4,830 feet high, approached by a dangerous path leading to a village of the Hanensha tribe, the most elevated group of habitations in Tunis.
Farther east, towards the geographical centre of the country, the plateaux are large and uniform enough to have received the name of hamâda, like the stony plains of the desert. Here the whole region culminates in the Jebel Berberu (4,920 feet), the Ras Si Ali-bu-Mussin (5,050), and the Jebel Haluk (4,810). Kessera most regular of the hamâdas, whose summit consists of an enormous table
10 square miles in extent, contains a small sebkha in one of its depressions, and its precipitous slopes are almost everywhere densely wooded.
North-cast of the central hamâdas the uplands develop a regular mountain range, which comprises the Jebel Jugar and the superb Zaghwan, which during the Roman epoch gave the name of Zeugitana to the whole of this highland region. Of all the Tunisian heights, none is more famous than that of Zaghwan, whose blue pyramidal crest (4,470 feet) is visible from Tunis. From the Jugar and Zaghwan hills Carthage drew its supply of water, and these sourees are still utilised by the modern capital. A conspicuous feature of the landscape is also the Jebel Ressas, or "Lead Mountain," to the south-east of Tunis, from which it is separated by the intervening valley of the Wed Melian. Another steep mountain, the Bu-Kurnein, or "Father of the Two Horns," rises immediately above the southern shore of the Gulf of Tunis, where it is recognised far seawards by its twin peaks resting on a massive foundation of reddish rocks.
