These plains are much higher than the sandstone ravines, and the soil contains not only pebbles, but angular fragments of the knots and fibres of wood in a silicified state, and much encrusted with chalcedony. The component parts of the sandstone in the gullies resemble those of a sea beach. These fragments of fossil wood in rich soils of plains or downs above formations of sandstone, are found in various parts of Australia, and I have seen fossil wood from similar plains in Tasmania. The fossil wood of such plains has no appearance of having been exposed to fire. The ACACIA PENDULA grows on the skirts of them, and indicates a salsolaceous soil. These circumstances are obvious to everybody, but no geologist has yet explained to us the causes of such changes as may have produced that rich black mould, on which trees, now silicified, formerly grew; or these wide plains and downs of rich earth, above a red sandstone formation. One has called the interior of Australia a "dry seabottom;" but this phrase admits of no easy application to such cases as these. Fragments of a ferruginous conglomerate of water-worn pebbles, apparently identical with those in the basin of the Darling, in some places accompany these angular fragments of fossil wood. We found this day a new ERIOSTEMON allied to E. BREVIFOLIUM, with small knobby fleshy leaves[*]; also a fine new shrubby EURYBIA.[**] Scattered plants of BOSSIOEA RHOMBIFOLIA also appeared in the adjacent gullies; and LORANTHUS SUBFALCATUS (Hook), was parasitical on trees. We encamped on the margin of the rich plain N. of Camp XLIX, and about a mile distant from it, our draught oxen being very weak and leg-weary. Thermometer, at sunrise, 25 deg.; at noon, 67 deg.; at 4 P.M., 73 deg.; at 9, 44 deg.;--with wet bulb, 40 deg.. [* E. RHOMBEUM (Lindl. MS.); ramulis pubescentibus, foliis carnosis obtuse rhombeis revolutis subtus glabris, pedicellis terminalibus unifloris tomentosis foliis brevioribus, staminibus pilosis.] [* E. SUBSPICATA (Hook. MS.); foliis linearibus obtusis supra glabris subtus ramisque albo-tomentosis, corymbis terminalibus spiciformibus, involucri squamis lineari-oblongis albis apice viridipunctatis.]