T

his is a transitional zone between Black Sea and Aegean Regions; it lies each side of the Sea of Marmara, a continuation of the line of depressions of the Black Sea Region. Thrace, which forms the European part of Turkey, is flattened plateau covered with recent sedimentary deposits along which runs the rang of the Istranca Mountains. The only large river Meriç (Maritza) serves as a frontier between Greece and Turkey.

The Straits, the Dardanelles and the Bosphorus, are old river valleys which the sea penetrated. A surface current drains the fresh water of Black Sea into the Mediterranean, while a deep counter-current of salt water flows from the Mediterranean into the Black Sea. The Dardanelles are about 65 kms/40 miles long with an average width of 4 kms/2.5 miles (minimum: just over 1,200 meters/3,937 feet) at ÇANAKKALE. The Bosphorus, which winds about a great deal, is 26 kms/16 miles long and has an average width of about 1.5 kms/0.9 mile (about 600 meters/1,969 feet) at Kandilli). The existense of a wide, deep gulf, the GOLDEN HORN, at its southern end favoured the building of a town on the peninsula separating the gulf from the Sea of Marmara, and so it was that the great city of Bayzantium grew up, later to become Constantinopolis and then İstanbul.

While the inland region still enjoys a Black Sea type of climate, with fairly high rainfall and some fine forestland on the heights, the basins with their more distinctly Mediterranean climate are hotter and less well watered; cereals, vines, and mulberries are grown here. Thrace, on the other hand, is affected by the continental influence of the Balkans: the winters are often severe, but in summer the heat is not excessive.