It will be seen from the map on page 201 that in this part of the country, to the north-east of Baghdad, a range of hills, the Jebel Hamrin, cuts across the district lying between the Tigris and the Diala rivers, and even extends beyond the Diala southward. This range, a mass of difficult highlands, was held by the Turks, and was a formidable obstacle to any advance against them, while from its lower spurs issued a great system of canals upon which depended the fertile tracts below. To complete the expulsion of the Turks from these tracts, rich in supplies, and to prepare for a further advance in the future, General Maude’s right-hand force now pushed on and seized the head works of the canals, penetrating some way into the Jebel Hamrin. There they established themselves, opening up the country with great labour by bridging the canals and making roads. General Marshall, who commanded the force, writes that “seventy-five bridges of various sizes were built in this area alone, and the Jebel Hamrin, which prior to our occupation was a roadless tangle of hills, was gradually pierced by a very complete and convenient number of roads suitable for wheeled traffic.”[58] Thus both on the Euphrates and on the Diala, to left and right, General Maude had freed himself from immediate enemy pressure. It remained to deal with the Turks to the north on the Tigris. These, consisting of his old enemy the 18th Corps, greatly reinforced, had not been passive spectators of the British movements on the two flanks. They did not move in time to prevent or hamper these movements, but in the middle of October 1917 they pushed down the Tigris for a considerable distance below their strong intrenched position at Tekrit, and assumed a threatening attitude. General Maude at once struck at them in front, and bringing in the Cavalry from his wings, tried at the same time to work round their flanks, the result being that they retired again to Tekrit, and there gave battle. It was a strong position--“an intricate system of trenches, many of which had been well and deeply dug, with numerous machine-gun emplacements”; and, as every one knows, the Turks in such a position are among the most tenacious soldiers in the world.