"كتيّب بلاد الرافدين. المجلد I. ١٩١٨" [‎١‎١] (٥٦٨/٢٠)

BOUNDARIES AND PHYSICAL FEATURES 11
Relation to International Lines of Communication
While at its southern extremity the Mesopotamian depression
opens on to the Persian Gulf ? at its north-western corner, between
the trough of the Euphrates and the passes of the Giaour Dagh ? which
give access to the Gulf of Alexandretta and the south-eastern corner
of Anatolia, there lies only a belt of easy country 70-120 miles
broad (the northern corner of Syria). Thus the Mesopotamian plains
and lower hill-country form a great corridor, which, shut in between
the mountains on the one side and the desert on the other, connects
the eastern Mediterranean and southern Anatolia with the Persian
Gulf, and thus, again, this country is a stage on the most direct
line of communication between central or southern Europe and
southern Asia.
Further, the most direct lines of approach from the eastern end of
the Mediterranean (the Levant) to the Persian plateau and so to
central Asia lie across the northern and central part of Mesopotamia.
The mountains on the western side of the Persian plateau over
looking Mesopotamia are, almost everywhere, a very difficult barrier;
but there is one marked natural gate through them—the depression
in the ranges near Qasr-i-Shlrln, about 110 miles NE. of Baghdad.
From Sivas in eastern Anatolia, an important route-centre, which
is connected by main routes w T ith the Black Sea port of Samsun and
with Constantinople through central Anatolia, there is a line of
communication with Diarbekr in northern Mesopotamia by way
of Kharput and the Arghana defile through the Taurus, and from
Diarbekr easy lines can be found through Mesopotamia to Baghdad
and the Persian Gulf or central Persia. But the direct main line
of communication between Sivas or the Black Sea port of Trebizond
and north-west Persia passes north of Lake Van by Erzerum and
Bayazid to Tabriz, and therefore lies outside our area.
Geographical Divisions and their Surface
In describing the surface of particular regions within the whole
area under consideration, it will be convenient to make a division
between Lower and Upper Mesopotamia.
Lower Mesopotamia and the Adjoining Country
Under this heading fall [a) the alluvial plains of Irak and Arabistan,
(b) the borderland of hill-country and mountains dividing these plains
from the Persian plateau, together with the depression in the