The valley of the river being rocky and impassable above the camp, we crossed to the left bank and ascended the sandy tableland; steered about south-east from 7.45 a.m. to 11.0, when we came on the stream in a deep valley formed by almost perpendicular red sandstone cliffs from 50 to 200 feet in height, broken at short intervals by enormous fissures (their general direction west-north-west and nearly at right angles with the river), which time, with the action of water, had worn into impassable ravines, frequently extending more than half a mile back from the river, and rendered travelling very tedious and unsafe, as it was requisite to avoid the thick scrubs covering the higher land. The course of the river now changed to nearly south, and preserved the same rocky and unapproachable character till 5.0 p.m., when a break in the cliffs enabled us to descend into the valley, although with some difficulty and danger to the horses, which had to slide down the steep rocks at the risk of breaking their necks, which would have been the almost certain result of a single false step; but the descent being accomplished, they were rewarded by an abundant supply of grass and water, the latter from a large spring at the foot of the cliffs. 10th October. While breakfast was preparing, Mr. Burges and myself examined the right bank of the river, and after a short search, found a practicable ascent to the top of the cliffs, and having cleared a way through the thicket of melaleuca on the bank of the river, returned to breakfast. At 7.50 a.m. commenced ascending, and at 8.30 reached the summit of the rocky hills, and steering about south-east through a succession of thickets, rocks, yawning chasms, sand-hills, and scrub, we attained to a fine grassy flat at 12.30 p.m. The bed of the river here quite changed its character, the sandstones giving place to granite gneiss, with dark trap dykes intersecting it in a northerly and southerly direction, the dip of the strata being to the west at a very high angle, at times almost perpendicular. A DEPOT CAMP. EXPLORE THE UPPER MURCHISON. 11th October.