The discovery of this vast and as yet imperfectly known tract of country, was made in the year 1814, and will doubtless be hereafter productive of the most important results. It has indeed already given a new aspect to the colony, and will form at some future day, a memorable era in its history. Nothing is now wanting to render this great western wilderness the seat of a powerful community, but the discovery of a navigable river communicating with the western coast. That such exists, although the search for it has hitherto proved ineffectual, there can be no doubt, if we may be allowed to judge from analogy; since in the whole compass of the earth, there is no single instance of so large a country as New Holland, not possessing at least one great navigable river. To ascertain this point has been one of the leading objects of Governor Macquarie's administration, ever since the discovery of the pass across the mountains. Several unsuccessful expeditions have been fitted out with this view from Sydney, both by sea and land. The last of which we have learned the result, was conducted by Mr. Oxley, the surveyor-general, and is most worthy of notice, as well from the extent of country which he traversed, as from the probability that the river which he discovered, discharges itself into the ocean on some part of the western coast. The summary of this journey is contained in the following letter, addressed by him to the governor on his return from this expedition to Bathurst Plains. _Bathurst, 30th August_, 1817. SIR, I have the honour to acquaint your Excellency with my arrival at this place last evening, with the persons comprising the expedition to the westward, which your Excellency was pleased to place under my direction. Your Excellency is already informed of my proceedings up to the 30th of April. The limits of a letter will not permit me to enter at large into the occurrences of nineteen weeks; and as I shall have the honour of waiting on your Excellency in a few days, I trust you will have the goodness to excuse the summary account I now offer to your Excellency. I proceeded down the Lachlan in company with the boats until the 12th of May, the country rapidly descending until the waters of the river rose to a level with it, and dividing into numerous branches, inundated the country to the west and north-west, and prevented any further progress in that direction, the river itself being lost among marshes: up to this point it had received no accession of waters from either side, but on the contrary was constantly dissipating in lagoons and swamps.