Nearly 85% of the land is at an elevation of at least 450 meters; the average and median altitude of the country is 1,332 and 1,128 meters, respectively. In Asiatic Turkey, flat or gently sloping land is rare and largely confined to the deltas of the Kızıl River, the coastal plains of Antalya and Adana, and the valley floors of the Gediz River and the Büyükmenderes River, and some interior high plains in Anatolia, mainly around Tuz Gölü (Salt Lake) and "Konya Ovası" (Konya Plain). Moderately sloping terrain is limited almost entirely outside Thrace to the hills of the Arabian Platform along the border with Syria.