Farther to the north the wall is still buried under the rubbish as far as its eastern termination, where it starts again from another great outstanding bastion to the north of the Ishtar Gate, and there rests against the exactly similarly constructed bastion of the older moat wall. This older moat wall runs on almost the same lines as the later one, but somewhat within it. Like the latter it is laid with asphalt and reeds, but has smaller unstamped bricks, measuring 32 × 32 centimetres. In the trench near the Persian building we found it at a great depth, and excavated the northern portion of it with the corner bastion, in the angle of which is a well, this time a walled one. A tablet that referred to the construction of this well was found close by. The wall rests on a broad foundation banquette, and stretches in an easterly direction, ending with a substantial tower at the Arachtu wall of Nabopolassar, and reappearing at the Ishtar Gate with the above-mentioned outstanding bastion. Here we can recognise a later addition, a raising of the wall, for the strengthening of which powerful beams are jointed in. The lower part has a slight batter, and was later washed over with asphalt, like the walls of Nabopolassar’s palace, which we have already described. In the well-built but not deeply-founded cross wall, between the bastion and the Ishtar Gate, a broad doorway with a flight of steps led down westward from the level of the earlier Procession Street. It is possible that the bastions were symmetrically repeated on the other side of the street, but the site has not yet been excavated. XXII THE ARACHTU WALL OF NABOPOLASSAR AND THE WALL OF SARGON THE ASSYRIAN. North-west of the palace of Nabopolassar, and deep below the three fortification walls which here lie in front of the Southern Citadel, there are the remains of four ancient walls, the discovery of which has been of great importance for the topography of Babylon. All four are the rounded-off corners—if we may call them so—of quay walls which slope sharply on their north and west fronts. All four are built with a lavish number of stamped and inscribed bricks, so that no doubt whatever can exist as to their use and name. Each of these quay walls represents a rebuilding of the one behind it, and indicates a thrusting forward of the quay front to the north and west. They consist of good burnt brick, and are for the most part laid in pure asphalt (section on Fig. 87).