Bounded on the north by the range of hills which Strabo calls Mons Masius, and on the east by the waterless upland which lies directly west of the middle Tigris, it comprises within it all the numerous affluents of the Khabour and Bilik, and is thus better supplied with water than almost any country in these regions.

The borders of the streams afford the richest pasture, and the whole tract along the flank of Masius is fairly fertile.

Towards the west, the tract between the Khabour and the Bilik, which is diversified by the Abd-el-Aziz hills, is a land of fountains.

"Such," says Ibn Haukal, "are not to be found elsewhere in all the land of the Moslems, for there are more than three hundred pure running brooks." Irrigation is quite possible in this region; and many remains of ancient watercourses show that large tracts, at some distance from the main streams, were formerly brought under cultivation.
Opposite to Mesopotamia Proper, on the west or right bank of the Euphrates, lay Northern Syria, with its important fortress of Carchemish, which was undoubtedly included in the Empire.

This tract is not one of much value.