mountains. The range rises just inland from the coast and trends generally in an easterly direction until it reaches the Arabian Platform, where it arcs around the northern side of the platform. The Taurus Mountains are more rugged and less dissected by rivers than the Pontic Mountains and historically have served as a barrier to human movement inland from the Mediterranean coast except where there are mountain passes such as the historic Cilician Gates (Gülek Pass), northwest of Adana. Central Anatolia Region Stretching inland from the Aegean coastal plain, the Central Anatolia Region occupies the area between the two zones of the folded mountains, extending east to the point where the two ranges converge. The plateau-like, semi-arid highlands of Anatolia are considered the heartland of the country. The region varies in elevation from 700 to 2000 meters from west to east. Mount Erciyes is the peak at 3916 meters. The two largest basins on the plateau are the Konya Ovası and the basin occupied by the large salt lake, Tuz Gölü. Both basins are characterized by inland drainage. Wooded areas are confined to the northwest and northeast of the plateau. Rain-fed cultivation is widespread, with wheat being the principal crop. Irrigated agriculture is restricted to the areas surrounding rivers and wherever sufficient underground water is available. Important irrigated crops include barley, corn, cotton, various fruits, grapes, opium poppies, sugar beets, roses, and tobacco. There also is extensive grazing throughout the plateau. Central Anatolia receives little annual rainfall. For instance, the semi-arid center of the plateau receives an average yearly precipitation of only 300 millimeters. However, actual rainfall from year to year is irregular and occasionally may be less than 200 millimeters, leading to severe reductions in crop yields for both rain-fed and irrigated agriculture. In years of low rainfall, stock losses also can be high. Overgrazing has contributed to soil erosion on the plateau. During the summers, frequent dust storms blow a fine yellow powder across the plateau. Locusts occasionally ravage the eastern area in April and May. In general, the plateau experiences extreme heat, with almost no rainfall in summer and cold weather with heavy snow in winter. Frequently interspersed throughout the folded mountains, and also situated on the Anatolian Plateau, are well-defined basins, which the Turks call ova. Some are no more than a widening of a stream valley; others, such as the Konya Ovası, are large basins