Its course among the mountains is from 80 to 90 miles, exclusive of small windings; and it runs more than 100 miles through the plain.

Its ordinary width, just above its confluence with the Tigris, is 25 feet.
The Diyaleh, which lies mostly within the limits that have been here assigned to Assyria, is formed by the confluence of two principal streams, known respectively as the Holwan, and the Shirwan, river.

Of these, the Shirwan seems to be the main branch.

This stream rises from the most eastern and highest of the Zagros ranges, in lat.

34 deg.