He noticed that throughout this route, in spite of the dry weather, the cattle were all in good condition; and he found Oxley's swamps and marshes transmuted into grassy flats.

In fact, so changed was the face of the land, that even the landmarks of that explorer could scarcely be recognised.
Again his mind began to be troubled with doubts as to whether he had not acknowledged the veracity of Sturt's judgment too hastily, for we find in his journal that he again wavered, after professing that the identity admitted of little doubt.

Now, on the Lachlan, he reverted to his old idea that the Darling drained a separate and independent basin of its own.

He wrote:-- "I considered it necessary to ascertain, if possible, and before the heavy part of our equipage moved further forward, whether the Lachlan actually joined the Murrumbidgee near the point where Mr.Oxley saw its waters covering the face of the country, or whether it pursued a course so much more to the westward as to have been mistaken for the Darling by Captain Sturt." Impelled by this doubt he undertook a long excursion to the westward with no result but the discomfort of several thirsty nights and an unchanging outlook across a level expanse of country bounded by an unbroken horizon.
He reached Oxley's furthest on the 5th of May, but did not find that explorer's marked tree, though he found others marked by Oxley's party with the date 1817.
On the 12th of May, he halted on the bank of the Murrumbidgee, which in his opinion surpassed all the other Australian rivers he had yet seen.

As his orders were simply to clear up the last hazy doubts that wrapped the Murray and Darling junction, and then to visit the southern bank of the Murray, he did not take his heavy baggage on to the Darling, but formed a stationary camp on the Murrumbidgee, and thence went on with a small party.