Down the Tigris from Ashur there are no important ancient towns till the old glacial shore line is reached and the true alluvial valley begins. Here there are the first traces of ancient irrigation. The site of Opis, Upe, is probably on the Tigris close to its junc ture with the Adhem. Apart from the site of Baghdad, which has always been an important centre and Ctesiphon, a little lower down the river the ancient cities from this point onwards lay on the old bed of the Euphrates. The most northerly of these cities is Sippar, probably on the actual edge of the glacial shore-line, and five miles from the present bed of the Euphrates. From this point onwards the traveller who abandons the modern river and passes along the old bed of the stream and the canals which have succeeded it will find a continuous string of imposing mounds in what is today a bare and monotonous plain, fringed along the western horizon by the palm trees which mark the course of the Euphrates. South of Sippar lay Agade, the city whose name is as sociated with that of Sargon. Cutha lay on the canal of Cutha, which may in ancient times have been one of the branches of the river. Below Cutha again, on what is today the Shatt-al-Nil, but which in ancient times was certainly the main stream, lay the great city of Kish. Fifteen miles westwards of Kish are the ruins of Babylon. These are today close to the Hilla branch of the Euphrates and since the foundation of the city it has always been on the river. It is from this point onwards that the main con trasts between ancient and modern Mesopotamia begin. When the river changed its course and flowed south past Babylon it deserted a whole line of ancient riparian cities and today there are only two ancient cities west of the modern course of the Eu phrates, Borsippa, close to Babylon, and Ur far to the south. The modern Shatt-al-Nil and the Shatt-al-Kar follow more or less the course of the ancient stream. Nippur lay south of Kish on the main river. Below Eridu there is only one ancient site, near Suk-esh-Shiyukh and all the modern marshland was non-existent. It is probable that southern Sumer consisted of a series of lakes and that much of what is now marshland was open water, although higher up the stream it is probable that marshes were still in existence. Otherwise the scenery of ancient Mesopotamia was probably not very different from what it is today, except for the alteration in position of the cities. Akkad, the northern allu vial plain, had the same steppe, the same fringing gallery of palms along the river, but this fringing gallery was at Kish and Nippur not at Hilla and Diwaniya. Where there are modern towns on the river there was desert or steppe, just as today the ancient cities are mere mounds waterless and bare. Southern Mesopo tamia, Sumer, has altered considerably; most of the lakes have filled up, though they may recall their ancient form in flood time. The lakes have been succeeded by marshes and though some of these survive many have been transformed into steppe and desert. In each of the three areas there has always been a dominant town, shifting under the change of the rivers; in Assyria, Mosul is the direct descendant of ancient Nineveh and the site is almost the same. In Akkad the changes have been greater; the oldest paramount town is Kish. Agade was only temporarily important, and the hegemony shifted to Babylon and across the narrow neck of land to Seleucia and Ctesiphon on the Tigris, and later to Bagh dad, itself on an ancient Sumerian site. In the south the changes have been greater. Larsa and Ur have ceased to hold a position of dominating geographical position, and the outlet of southern Mesopotamia passed under the Caliphs to Basra nearer to the Persian gulf. The true geographical history of Mesopotamia has a clear cut at the invasion of the Mongols and from this point begins the study of the modern cities.
Modern Geography.—Modern Mesopotamia, now the king dom of Iraq, occupies most of the geographical region of Mesopo tamia, although the eastern bank of the Shatt-al-Arab is under the Persian rule. It also extends westwards along a corridor into the Syrian desert. The delimitation of frontiers on the north and
west has been a matter of considerable difficulty. It has been recognized that for pastoral nomads a sharply defined frontier, except where there are marked physical boundaries, is hardly possible. The nomads recognize definite frontiers, but these fron tiers are rather to be expressed as grazing and water rights than as a definite line. These rights have been recognized and the frontiers allow the nomads to exercise their grazing rights irrespective of where the actual line has been drawn. Recent disturbances along the south-western border of Iraq have however shown that the existence of a paper frontier, even while it maintains traditional rights, will not always be a deterrent to raiding tribes. With these reservations however the frontiers of Iraq have now been delim ited, and suitable allowance has been made for a zone in which grazing rights belong by ancient tradition to tribes on one side or other of the boundary. In the western corridor however the fron tier is not at present clearly defined. It is extremely difficult to plot a frontier where the boundary is defined by natural features but where these features are not definitely located. Jebel Anaza is mentioned in the agreement and is stated to be 32° N. and 39° E., but Musil's map gives a location about two degrees south of this position. This western corridor is of considerable impor tance to modern Iraq. It is used at present as a motor route form ing one of the readiest means of transporting passengers between Jerusalem and Baghdad. It is also used today by the Imperial airways who have a series of landing grounds plotted out between Amman and Rimadi.
Communications.—Apart from the airway and motor route Iraq possesses no direct communication by modern methods of transport except by sea to Basra. Internal communications are however better. During the World War a temporary line was laid along the lower Tigris. Since that time this line has been dis mantled and a line from Baghdad to Basra along the Euphrates has been substituted, with a short branch to Kerbela. North of Baghdad there are two lines. One, standard gauge, runs to Kalat Shergat. This line is part of the proposed Baghdad railway. The original intentions of the builders were for this line to run north wards through Mosul and eventually by Nisibin and so connect with the Asia Minor and Syrian systems. The metre gauge runs along the Tigris to railhead at Kerkuk. It has recently been sug gested that this line should be carried on to Mosul, as it travels through a comparatively highly populated area, whereas the old line would have to pass through practically uninhabited desert. As it is, the third most important town in Iraq is entirely without railway communications. Considering the size of Iraq it is at pres ent extremely badly provided with railways, the most recent figures available being About six hundred thousand passengers are carried a year.
In connection with the railways other communications have been developed. There is a weekly motor service connecting Bagh dad and Syria, running across the desert to Damascus. From Kerkuk a new trade route has been developed to Tabriz via Ru wanduz, and Bulagh. The caravans go laden with teas and return with almonds and dried fruits which are sold in Baghdad. The second route via Khanakin does not seem at present to be very successful. There is a fairly regular service of cars to Teheran. In addition to the fortnightly air service with Cairo there are also air services between Baghdad and Mosul and Kerkuk and Sulaimaniya.
Apart from native boats the river services are practically limited to the Shatt-al-Arab and the Tigris. Sir William Willcocks was of opinion that the railways should be used for communications and the rivers for irrigation. Considerable divergence of opinion has existed on this point, but although developments seem quite possible (see TIGRIS ; EUPHRATES) no great advances have been made at present. The most recent development of a river service has been between Basra and Siba, the Iraq frontier station opposite the Anglo-Persian refinery at Abadan.