part of the chain of Atlas Mountains, extending across northern Africa from Algeria into Tunisia. The principal ranges from west to east are the Ksour, Amour, Ouled-Naïl, Zab, Aurès, and Tébessa (Tabassah). Mount Chélia (7,638 feet 【2,328 m】) is the highest point in northern Algeria, and ash-Shaʿnabī (Shaʿnabī, Mount Ash-) (5,066 feet 【1,544 m】) is the highest peak in Tunisia. Iron ore is mined near Mount Ouenza, and there are extensive phosphate deposits near the town of Tébessa, both in Algeria.