By the constant westward pressure of the eastern Arabs, which (after the restraining force of the great Mesopotamian kingdoms was weakened) assumed irresistible strength, the ancient Edomites were forced across the Jordan-Araba depression, and with their name migrated to the south of western Palestine.
This large influx of Europeans, however, is modifying the population by reducing the Indian and mestizo elements to a minority, although they are still numerous in the mesopotamian, northern and north-western provinces.
Two days' journey beyond Rakka, where the Euphrates breaks through the basalt dike of el-IIamme, are two admirably preserved ruins, built of gypsum and basalt, that on the Mesopotamian side called Zelebiya (Chanuga), and that on the Syrian, much the finer of the two, Halebiya or Zenobiya, the ancient Zenobia.
This, however, is a feature common to Mesopotamian and Egyptian, and perhaps to all primitive art.
All this drainage, collected into two rivers, the Belikh and the Khabur, is towards the left bank of the Euphrates, for the Mesopotamian watershed seems to be only some 15 m.