At the close of the year 1829, I was again sent into the interior to trace its streams and to ascertain the further course of the Darling.  I proceeded on this occasion to the south of Sydney, and intersecting the Murrumbidgee, a river at that time but little known, but which Mr. Hume had crossed, in lat. 35 degrees 10 minutes, and long. 147 degrees 28 minutes 30 seconds E., on his journey to the south coast, at a very early period of discovery, and which thereabouts is a clear, rapid and beautiful stream.  I traced it downwards to the west to lat. 34 degrees 44 minutes, and to long. 143 degrees 5 minutes 0 seconds E. or thereabouts, having taken to my boats a few miles above the junction of the Lachlan with it, in lat. 34 degrees 25 minutes 0 seconds and in long. 144 degrees 3 minutes E.; having at that point left all high lands 200 miles behind me, and being then in a low and depressed country, precisely similar to that over which I had crossed the previous year.  As on the first expedition, so on the present one, I descended rapidly into a country of general equality of surface; reeds grew in extensive patches along the line of the river, but beyond them sandy plains extended, covered with salsolae of various kinds.  From the Murrumbidgee, I passed into the Murray, the largest known river in Australia, unless one of greater magnitude has recently been discovered by Sir Thomas Mitchell to the north.

In lat. 34 degrees and in long. 142 degrees, I arrived, (as I have already had occasion to inform my readers), at the junction of a very considerable stream with the Murray.  At this point, being then 200 miles distant from the south coast in a direct line, I was less than 100 feet above the level of the sea; circumstances prevented my examining this new river however for many miles above its junction with the main stream, but coming, as I have elsewhere remarked, direct from the north, and possessing, as it did, all the character and appearance of the Upper Darling, I had no doubt as to its identity; in which case no stronger fact could have been adduced to prove the southerly fall or dip of the interior as far as it had been explored.  Proceeding down the Murray, I reached at length the commencement of the great fossil formation, through which that river flows.  This immense bed rose gradually before me as I pushed to the westward, until it gained an elevation of from 2 to 250 feet, but on my turning southward, it presented an horizontal and undulating surface, until at the point at which the river enters the Lake Victoria, it suddenly dipped and ceased.  The lower part of this formation was entirely composed of Serritullae, but every description of shell with the bones and teeth of sharks and other animals, have subsequently been found in the upper parts of the bed, the summit of which is in many places covered with oyster shells so little changed by time, as to appear as if they had only just been thrown in a heap on the ground they occupy.