evidence: Lebanon is divided into four distinct physiographic regions: the coastal plain, the Lebanon mountain range, the Beqaa Valley and the Anti-Lebanon Mountains. The narrow and discontinuous coastal plain stretches from the Syrian border in the north where it widens to form the Akkar plain to Ras al-Naqoura at the border with Israel in the south. The fertile coastal plain is formed of marine sediments and river deposited alluvium alternating with sandy bays and rocky beaches. Lebanon's mountains rise steeply parallel to the Mediterranean coast and form a ridge of limestone and sandstone that runs for most of the country's length. The mountain range varies in width between 10 km (6 mi) and 56 km (35 mi); it is carved by narrow and deep gorges. The Lebanon mountains peak at 3,088 metres (10,131 ft) above sea level in Qurnat as Sawda' in North Lebanon and gradually slope to the south before rising again to a height of 2,695 metres (8,842 ft) in Mount Sannine. The Beqaa valley sits between the Lebanon mountains in the west and the Anti-Lebanon range in the east; it is a part of the Great Rift Valley system. The valley is 180 km (112 mi) long and 10 to 26 km (6 to 16 mi) wide, its fertile soil is formed by alluvial deposits. The Anti-Lebanon range runs parallel to the Lebanon mountains, its highest peak is in Mount Hermon at 2,814 metres (9,232 ft).[183]