We find further confirmation of this view in one of the later quay-walls, which succeeded that of Sargon. The three narrow walls already referred to[47] were all the work of Nabopolassar, and represent three successive extensions of the quay westward into the bed of the stream, which in the inscriptions upon their bricks is given the name of Arakhtu.[48] But the texts make no mention of the city-walls. No inscriptions at all have been found in the structure of the next extension, represented by the wall B, which, like the latest quay-wall (C), is not rounded off in the earlier manner, but is strengthened at the corner with a massive rectangular bastion. It was in this latest and most substantial of all the quay-walls that further inscriptions were found referring to Imgur-Bêl. They prove that this wall was the work of Nebuchadnezzar, who refers in them to Nabopolassar's restoration of Imgur-Bêl and records that he raised its banks with bitumen and burnt-brick mountain-high. It is therefore clear that this was the quay-wall of Imgur Bêl, which it supported in the manner of Sargon's earlier structure. That the less important Nimitti-Bêl is not mentioned in these texts does not necessitate our placing it elsewhere, in view of Sargon's earlier reference. We may therefore provisionally regard the two crude-brick walls along the Ḳaṣr's northern front[49] as a section of the famous defences of Babylon, and picture them as running eastward till they meet the inner city-wall by Homera. The point at which they extended westward across the Euphrates can, as yet, only be conjectured. But it is significant that the angle of the western walls, which may still be traced under mounds to the north of Sinjar village,[50] is approximately in line with the north front of the Ḳaṣr and the end of the inner wall by Homera. Including these western walls within our scheme, the earlier Babylon would have been rectangular in ground-plan, about a quarter of it only upon the right bank, and the portion east of the river forming approximately a square. The Babylon of the Kassite period and of the First Dynasty must have been smaller still, its area covering little more than the three principal mounds; and, though part of its street net-work has been recovered, no trace of its fortifications has apparently survived.