April 11.--We continued our journey up the river, in a W.N.W. direction, for about ten miles. The first part of our journey lay through a most beautiful country. The hollows along the river were covered with a dense sward of various grasses, and the forest was open as far as the eye could reach. Farther on, however, we occasionally met with patches of Vitex scrub, and crossed some stony ridges. A small river joined from the north-east, at about a mile and a half from the last camp, and also two large creeks from the south-west. I ascended the hills opposite our camp, and looked over an immense and apparently flat country, out of which small peaks and short ranges rose. The hills on which I stood were composed of Pegmatite, with patches of white Mica in large leaflets. During the journey we found granite changing into gneiss, diorite, and quartz rock. On the rocky crest of the hill, I gathered the pretty red and black seeds of a leguminous climbing shrub (Abrus precatorius). Phonolithic or basaltic pebbles made me suppose that we were near to a change of country. Our latitude was 19 degrees 58 minutes 11 seconds. April 12.--We had scarcely travelled a mile and a half, when we had to cross a large creek, which increased in size higher up. Box-tree flats and open Vitex scrub extended along its banks, and the latter, according to Mr. Roper's account, changed into dense Bricklow scrub. At the junction of the creek and the river, we came on a dyke of basalt, the flat summit of which was so rough that we were compelled to travel along the flats of the creek, which for a long distance ran parallel to the Burdekin. The soil on the basalt was so shallow that it sustained only a scanty vegetation of grass and some few scattered narrow-leaved Ironbark trees. We crossed this dyke, however, and at about three miles descended from it into a fine narrow-leaved Ironbark flat, extending along the river, in which another large creek from the south-west joined the Burdekin. The flat was bounded by hills of limestone, cropping out in large blocks, with visible stratification, but without fossils. Having passed the third creek in the course of this day's journey, we encamped on the commencement of another basaltic dyke. The bed of the creek was full of blocks of Sienite, of hornblende Porphyry, of greenish Pegmatite, and of cellular Basalt. The river here formed a large sheet of water; large masses of a white Sienite protruded out of it, opposite the junction of the creek. The opposite bank exhibited a very perfect and instructive geological section of variously bent and lifted strata of limestone, which was afterwards found to contain innumerable fossils, particularly corals and a few bivalve shells. The Rev. W. B. Clarke, of Paramatta, kindly undertook to examine the fossils brought from this locality. One he determined to be an undescribed species of Cyathophyllum, and has done me the honour to give my name to it [Refer Note 1 at end of chapter].