The course of the Kerkhah was not always exactly such as is here described.  Anciently it appears to have bifurcated at Pai Pul, 18 or 20 miles N.W. of Susa, and to have sent a branch east of the Susa ruins, which absorbed the Shapur, a small tributary of the Dizful stream, and ran into the Kuran a little above Ahwaz.  The remains of the old channel are still to be traced; and its existence explains the confusion, observable in ancient times, between the Kerkhah and the Kuran, to each of which streams, in certain parts of their course, we find the name Eulseus applied.  The proper Eulseus was the eastern branch of the Kerkhah (Choaspes) from Pai Pul to Ahwaz; but the name was naturally extended both northwards to the Choaspes above Pai Pul and southwards to the Kuran below Ahwaz.  The latter stream was, however, known also, both in its upper and its lower course, as the Pasitigris.

On the opposite side of the Empire the rivers were less considerable.  Among the most important may be mentioned the Sajur, a tributary of the Euphrates, the Koweik, or river of Aleppo, the Orontes, or river of Antioch, the Litany, or river of Tyre, the Barada, or river of Damascus, and the Jordan, with its tributaries, the Jabbok and the Hieromax.

The Sajur rises from two principle sources on the southern flanks of Amanus, which, after running a short distance, unite a little to the east of Ain-Tab.  The course of the stream from the point of junction is south-east.  In this direction it flows in a somewhat tortuous channel between two ranges of hills for a distance of about 30 miles to Tel Khalid, a remarkable conical hill crowned by ruins.  Here it receives an important affluent—­the Keraskat—­from the west, and becomes suitable for boat navigation.  At the same time its course changes, and runs eastward for about 12 miles; after which the stream again inclines to the south, and keeping an E.S.E. direction for 14 or 15 miles, enters the Euphrates by five mouths in about lat. 36 deg. 37’.  The course of the river measures probably about 65 miles.

The Koweik, or river of Aleppo (the Chalus of Xenophon), rises in the hills south of Ain-Tab.  Springing from two sources, one of which is known as the Baloklu-Su, or “Fish River,” it flows at first eastward, as if intending to join the Euphrates.  On reaching the plain of Aleppo, however, near Sayyadok-Koi, it receives a tributary from the north, which gives its course a southern inclination; and from this point it proceeds in a south and south-westerly direction, winding along the shallow bed which it has scooped in the Aloppo plain, a distance of 60 miles, past Aleppo to Kinnisrin, near the foot of the Jebel-el-Sis.  Here its further progress southward is barred, and it is forced to turn to the east along the foot of the mountain, which it skirts for eight or ten miles, finally entering the small lake or marsh of El Melak, in which it loses itself after a source of about 80 miles.