'IRAQ AND THE PERSIAN GULF' [‎65v] (135/862)

84 GEOLOGY AND DESCRIPTION OF THE LAND
Jabal Hamrin gorge, the river falls from 1,300 feet to 300 feet above
sea-level: 15 feet a mile for the first 35 miles and 13 feet a mile in the
second. It flows in a broad shingly bed uncovering many islands in
the low-water season. Near Qala Shirwana, 10 miles below the
Quraitu junction, it is a mile and a half wide in flood, has a strong
current, and is lined by willows, osiers, and shrubs. Lower down it
breaks up into numerous channels enclosing scrub-covered islands;
the channels may be from 20 to 50 yards wide and 4 feet deep in the
low-water season, but it is then fordable in many places.
The Ab-i-Abbassan crosses the Persian border 4 miles below the
Darband-i-Hul, its gorge through the Kuh-i-Bamu. The Quraitu Su
also breaks through the frontier range, here the Kuh-i-Bishkhan, at
the narrow Tang-i-Hammam defile and it then forms the boundary
for 14 miles. The Alwand or Hulwan enters a broad undulating plain
soon after reaching Iraq territory near the police post of Kani Baz,
about 6 miles east of Khanaqin. Its upper valley in Persia is used by
the modern motor-road to the Tak-i-Gireh pass (p. 571) and was
the route of the ancient Sassanid road through Qasr-i-Shirin. At
Khanaqin it has a low-water width of 60 yards and is generally
fordable, but it is also bridged (photo. 28; fig. 87). It has a 10-foot
rise in the flood season and then fills its flood-bed to a width of
100 yards or more.
Most of the country along the boundary is easily passable for pack
animals. In the north the Kuh-i-Bamu rises to 5,000 feet, but between
the Abbassan and the Quraitu even the frontier hills rarely reach
3,000 feet, and there are numerous tracks across them all the year
round leading to grazing-grounds of Persian Kurds. The boundary
north-east of Khanaqin follows the rounded crest of the Aq Dagh,
gypsum hills with gentle slopes on the west, covered with a reddish
nitrous soil and forming undulating grass-covered spurs separated by
gullies about 100 yards wide.
On the left bank of the Diyala undulating plains and low hills alter
nate. Both the triangular Shaikhan plain bordering the Ab-i-Abbassan
and the Quraitu plain are mostly under pasture, though some wheat,
barley, and maize are grown, particularly along the Quraitu, and there
are orchards near the villages. The Khanaqin plain is more closely
settled and much more fertile and better watered; regular irrigation
is practised from the Alwand below Khanaqin, which stands amidst
palms and other trees on both sides of the river (p. 539). Much of the
sub-soil of the Khanaqin plain is gravel, but is overlain by alluvium
from the rivers so that the going is heavy after rain. Barley, wheat, and