In his excavations on the site of the Apadana, he has been unable to verify the existence of the three bases belonging to the inner row of the northern colonnade. They were, however, among the first to be discovered by Mr. Loftus, and as he did not belong to the inventive group of travellers there can be no doubt they are to be found.[229] De Morgan is of opinion that the northern colonnade could never have contained more than a single row of columns, on account of the nature of the ground, which, he says, would not admit of more. His careful excavations between the central group and the lateral colonnades have proved the entire absence of any foundations upon which a solid structure could rest. It is clear, therefore, that the building could never have been enclosed by brick walls, adorned, as so commonly supposed, by enamelled designs. The theory supported by the Book of Esther that it was protected only by hanging curtains gains, therefore, probability, though we do not see that the supposition of its having been surrounded by wood is excluded. Below the foundations of Artaxerxes he found farther remains of the earlier edifice of Darius. Among these were the round base of a column and part of a bull-headed capital.[230] Elsewhere, lying at a still greater depth, he came upon a fluted column of a style entirely different from those in the more modern edifice. His investigations on the southern side have dispelled any hope of finding a sculptured staircase as at Persepolis.[231] His discoveries have contributed largely to widen the range of information concerning the ancient civilisation of Susiana. He has found upwards of eight hundred bricks bearing the inscriptions of various Elamite kings and patesis written in the Old Susian language; some of these are said to go back to B.C. 3000, or earlier, and a few of them are written, according to M. de Morgan, in Sumerian and others in Semitic. Besides bricks, a bronze bas-relief, and a few archaic tablets and a stele with Susian inscriptions have also been discovered. Other objects not of Elamite origin have been met which it is reasonable to conclude were captured in the course of successful raids. They go back to the earliest days of Babylonian history. One is an obelisk of a King of Kish who lived, it is said, so far back as B.C. 3850.[232] Another is a bas-relief of the famous Naram Sin carried off from Sippara; a third is a brick of the same king, a possible indication that he was at one time the suzerain of the country, and contributed to the embellishment of its temples. In addition to these, many boundary stones have been found, all relating to land in Chaldæa belonging to the late Cossaean period, which prove how successful the Elamites continued to be in removing their neighbours’ landmarks.[233]