The opposite banks of the river were ridgy, but openly timbered, and this fine country, with its well grassed flats, and its open ridges, seemed to extend very far on both sides.  Messrs. Gilbert and Roper went to the top of the hill, and saw ranges trending from west to north, with that crenelated outline which I had before seen and mentioned:  they distinguished a large valley, and the smoke of several fires of the natives along the range.  A large lagoon was at the western foot of the hill on which they were.  A large creek was seen, by Brown, to join the Burdekin from the north-east, at a short mile from our encampment.  A baked sandstone and pudding-stone of a white colour projected into the river at the place, which not only exhibited the transition from one rock into the other, but it showed the action of igneous rocks on both, and gave a clue to the nature of the red rock I described yesterday.  In the thicket which covered the rock, I observed Pomaderris of Moreton Bay.  In decreasing our latitude, both Mr. Gilbert and myself were inclined to think that, whenever a bird or a plant disappeared, it was owing to that circumstance.  In this, however, we were frequently mistaken:  trees and herbaceous plants disappeared with the change of soil, and the decrease of moisture, and the birds kept to a certain vegetation:  and, as soon as we came to similar localities, familiar forms of plants and birds re-appeared.  Almost all the scrub-trees of the Condamine and Kent’s Lagoon were still to be seen at the Burdekin; and the isolated waters near grassy flats were visited by swarms of little finches, which Mr. Gilbert had observed at Port Essington, and which, in all probability, belonged to the whole extent of country between that place and the region of the tropics.  This slight change of vegetation, and particularly of the inland Flora, from south to north, is no doubt connected with the uniformity of the soil and climate:  and the immense difference which exists between the eastern and western coast, has led men of science and of observation, not without good reason, to infer that this continent was originally divided into two large islands, or into an archipelago, which have been united by their progressive, and, perhaps, still continued, elevation.  As an exception, however, to this remark, a very sudden change of the Flora was observed, when we entered into the basin of the gulf of Carpentaria, after leaving the eastern waters, although the Flora of the north-west coast and Port Essington, was little different from that of the gulf.

April 17.—­We travelled about nine miles N. 40 degrees W. On our way we passed a hill of baked sandstone, and several gullies.  About five miles from our last camp, a large creek joined the river; beyond that creek, the country was, without exception, open, and rather of a more undulating character; the flats were somewhat rotten:  the river became narrower, but was still running strong; and numerous ducks sported on its shady pools.