'IRAQ AND THE PERSIAN GULF' [‎48v] (101/862)

54 GEOLOGY AND DESCRIPTION OF THE LAND
reached. Here the Hammar lake discharges the Euphrates waters
into the Shatt; beyond it the suburbs of Basra—the airport, Maqil,
Jubaila, and Ashar—follow in quick succession; Tanuma stands
opposite Ashar on the left bank; Basra itself is about 2 miles inland
on the right. The richest and densest date-groves in Iraq territory
are on the right bank of the river below Basra, where an almost
continuous belt of palms, from 1 to 2 miles wide, borders the river
to Fao. These groves are intersected with numerous tidal creeks,
irrigation channels, and mud embankments, which form a serious
obstacle, particularly in wet weather.
The Recession of the Head of the Persian Gulf The historical term used to describe the body of water between the Arabian Peninsula and Iran.
In the foregoing account of the Tigris and Euphrates the principal
historical changes of course have been briefly mentioned, and some
remarks have been made on the processes by which these changes
have come about. Before the long history of this ‘sea-land’ of lower
Mesopotamia can be properly understood, the coastline at different
periods must be examined. The six maps shown in fig. 14 have
been drawn on the basis of normal delta-forming processes, and on
two principal assumptions, namely, that the ancient Sumerian cities,
Eridu, Ur, Larsa, Kutalla, and Lagash, whose sites have been dis
covered and surveyed, were founded near the head of the gulf about
3,000 b.c., and that the rivers have brought down since that time
approximately the same amount of silt as they do to-day. Excepting
the last map, none pretends to accuracy at a particular date, but each
illustrates the general conditions prevailing within one or two hundred
years. Creeks in recently formed deltas constantly shift their channels;
these are generalized on all the maps except the last to illustrate the
type of delta formation at the particular period and not the actual
courses of the creeks; but the periods have been chosen to show the
major changes of course above the ‘wet deltas’ and below Kut al
Imara on the Tigris and Musaiyib on the Euphrates; they also illus
trate how the new courses may have been developed by natural causes.
Many of the more recently abandoned channels can be picked out
on the ground and on modern large-scale maps.
One of the most interesting events in the recession of the head of
the gulf is the date when the Karkheh-Karun delta reached the
rabian shore and formed a barrier enclosing the waters of the
Euphrates and Tigris. This would appear to have occurred between
500 3 00 b.c., both from geographical and historical evidence,
btrabo (c. 5 b.c.) writes that ‘the overflow of the water, falling into