"كتيّب بلاد الرافدين. المجلد I. ١٩١٨" [‎١‎٢] (٥٦٨/٢١)

12
BOUNDARIES AND PHYSICAL FEATURES
mountain-barrier NE. of Baghdad, and (c) the fringe of the Arabian
desert to the south-west of Irak. The whole of this area is about
95,000 square miles, or somewhat larger than Great Britain.
(a) The Alluvial Plains of IraJc and —A line drawn from
Delli Abbas 60 miles NNE. of Baghdad to Beled near the right
bank of the Tigris some 20 miles below Samarra, and thence to Hit
on the Euphrates, would roughly mark the northern limits of the
alluvial plain. Somewhat more exactly it may be said that, while
the Tigris begins near Beled to flow over an alluvial bed and between
strips of alluvial plain, and the bed of the Euphrates changes to
alluvium at Hit, in the area between the rivers the upper plain-
country runs down in a tongue of comparatively high-lying marl
desert almost to the line Baghdad—Fellujeh. To the north-east of
Baghdad the alluvium runs up along the Diyaleh to the foot of the
Jebel Hamrln.
The plains of Irak contain about 35,000 square miles, those of
Arabistan and the adjoining district of Behbehan about 17,000 square
miles. The alluvial country is in general a flat plain. In Irak the
only noticeable eminences are the mounds that mark the sites of dead
cities, the high banks of old canal-beds, and here and there knolls or
slight ridges of gravel or sand. In the northern part of Arabistan
there are a few low lines of sandstone hills, advanced outliers of the
hill-country, which run across the flats in a general NW.-SE.
direction.
The slope of the Irak plains from the neighbourhood of Baghdad
to the Persian Gulf is, as has been remarked above, very slight.
Baghdad is 105 ft. above sea-level, Kut el-Amara on the Tigris 55 ft.,
Nasirlyeh on the Euphrates 15 ft,, Basra 8 ft. There are also very
gradual downward inclines away from the rivers, and a slope from
the foot of the Persian hills to the neighbourhood of the Tigris;
these have great importance, both in determining the present flood-
areas and marshes, and also for projects of irrigation. In Arabistan,
along the line of the Karun, the slope from the foot of the hill-
country to the Persian Gulf is about 660 ft. in 175 miles (Dizful,
660 ft. above sea-level; Shushtar, 400 ft.; Ahwaz, 220 ft. ; Moham-
mareh, 7 ft).
The soil is mainly an argillaceous, calcareous loam of great fertility.
Pockets of stiff clay or pebbles, more or less sandy patches, and areas
of saline efflorescence occur here and there.
By far the greater part of the country is either marsh-land or arid
waste. The marsh-land is due to the annual river-floods, which rise
above the general levels of the country and are neither relieved by
escape-works nor confined by adequate dyking. The aridity of other