rivers, the Cydnus (Tarsus ÇayBerdan River), the Sarus (Seyhan), and the Pyramus (Ceyhan River), each of which brings down much silt from the deforested interior and which fed extensive wetlands. The Sarus now enters the sea almost due south of Tarsus, but there are clear indications that at one period it joined the Pyramus, and that the united rivers ran to the sea west of Kara-tash. Through the rich plain of Issus ran the great highway that linked east and west, on which stood the cities of Tarsus (Tarsa) on the Cydnus, Adana (Adanija) on the Sarus, and Mopsuestia (Missis) on the Pyramus. Climate The climate of Cilicia shows significant differences between the mountains and the lower plains. At the lower plains, the climate reflects a typical Mediterranean; summers are hot while winters are mild, making the land, particularly, the eastern plains, fertile. In the coldest month (January), the average temperature is 9 °C, and in the warmest month (August), the average temperature is 28 °C. The mountains of Cilicia have an inland climate with snowy winters. The average annual precipitation in the region is 647mm and the average number of rainy days in a year is 76. Mersin and surrounding areas have the highest average temperature in Cilicia. Mersin also has high annual precipitation (1096mm) and 85 rainy days in a year. Geology The Mountains of Cilicia are formed from ancient limestones, conglomerate, marlstone, and similar materials. The Taurus Mountains are composed of karstic limestone while its soil is also limestone-derived with pockets of volcanic soil. The lower plain is the largest alluvial plain in Turkey. Expansion of limestone formations and fourth era alluvials brought by the rivers Seyhan and Ceyhan, formed the plains of the region over the course of time. Akyatan, Akyayan, Salt Lake, Seven lakes at Aladağ, and Karstik Dipsiz lake near Karaisalı are the lakes of the region. The reservoirs in the region are Seyhan, Çatalan, Yedigöze, Kozan and Mehmetli. The major rivers in Cilicia are Seyhan, Ceyhan, Berdan (Tarsus), Asi and Göksu. Seyhan River emerges from the confluence of Zamantı and Göksu rivers which originate from Kayseri Province and flows into the Gulf of Mersin. The river is 560 km long. Ceyhan River emerges from the confluence of the Aksu and Hurman rivers and flows towards Cape Hürmüz at the Gulf of İskenderun. It is 509 km long and it forms the Akyayan, Akyatan,