From what he observed of the country, on both these occasions, he was led to infer that beyond the limits of his advance the interior had a uniform level, and was, for the most part, uninhabitable and under water. Its features must have been strongly marked to have confirmed such an opinion in the mind of the late Surveyor-General. It stands recorded on the pages of his journal, that he travelled over a country of many miles in extent, after clearing the mountains, which so far from presenting any rise of ground to the eye, bore unequivocal marks of frequent and extensive inundation. He traced two rivers of considerable size, and found that, at a great distance from each other, they apparently terminated in marshes, and that the country beyond them was low and unbroken. In his progress eastward, he crossed a third stream (the Castlereagh), about forty-five miles from the Macquarie, seemingly not inferior to it in size, originating in the mountains for which he was making, and flowing nearly parallel to the other rivers into a level country like that which he had just quitted. DISCOVERIES OF MESSRS. MECHAN, HUME, HOVEL AND CUNNINGHAM. Mr. Evans, moreover, who accompanied Mr. Oxley on these journeys, and who had been detached by his principal from Mount Harris, to ascertain the nature of the country in the line which the expedition was next to pursue, having crossed the Castlereagh considerably below the place at which the party afterwards effected a passage, reported that the river was then running through high reeds. The inference naturally drawn by Mr. Oxley, was, that it terminated as the Lachlan and the Macquarie had done; and that their united waters formed an inland sea or basin. It is evident that Mr. Oxley had this impression on his mind, when he turned towards the coast; but the wet state of the lowlands prevented him from ascertaining its correctness or error. Doubt, consequently, still existed as to the nature of the country he had left behind him; a question in which the best interests of the colony were apparently involved. Subsequently to these discoveries, Mr. Surveyor Mechan, accompanied by Mr. Hamilton Hume, a colonist of considerable experience, explored the country more to the southward and westward of Sydney, and discovered most of the new country called Argyle, and also Lake Bathurst.