Nevertheless, subsequent observations, recently made known by Colonel Rawlinson to the Geographical Society, have contradicted the views of Dr. Ross as stated above, and shown that the Wall of Media, in the line here assigned to it, has no evidence to rest upon. Captain Jones, commander of the steamer at Bagdad, undertook, at the request of Colonel Rawlinson a minute examination of the locality, and ascertained that what had been laid down as the Wall of Media was merely a line of mounds; no wall at all, but a mere embankment, extending seven or eight miles from the Tigris, and designed to arrest the winter torrents and drain off the rain water of the desert into a large reservoir, which served to irrigate an extensive valley between the rivers. From this important communication it results, that there is as yet no evidence now remaining for determining what was the line or position of the Wall of Media; which had been supposed to be a datum positively established, serving as premises from whence to deduce other positions mentioned by Xenophon. As our knowledge now stands, there is not a single point mentioned by Xenophon in Babylonia which can be positively verified, except Babylon itself,—and Pylæ, which is known pretty nearly, as the spot where Babylonia proper commences. The description which Xenophon gives of the Wall of Media is very plain and specific. I see no reason to doubt that he actually saw it, passed through it, and correctly describes it in height as well as breadth. Its entire length he of course only gives from what he was told. His statement appears to me good evidence that there was a Wall of Media, which reached from the Tigris to the Euphrates, or perhaps to some canal cut from the Euphrates, though there exists no mark to show what was the precise locality and direction of the Wall. Ammianus Marcellinus (xxiv, 2), in the expedition of the emperor Julian, saw near Macepracta, on the left bank of the Euphrates, the ruins of a wall, “which in ancient times had stretched to a great distance for the defence of Assyria against foreign invasion.” It is fair to presume that this was the Wall of Media; but the position of Macepracta cannot be assigned. It is important, however, to remember,—what I have already stated in this note,—that Xenophon did not see, and did not cross either the Wall of Media, or the two canals here mentioned, until many days after the battle of Kunaxa.