Left the bivouac at 8.15 a.m., and followed upwards the main branch of the Irwin to the north-north-east, through a steep and rocky valley, the sandstone hills in some parts approaching the river, so as to render it necessary to cross frequently with the pack-horses.  The very level character of the summits of these hills gives the country the appearance of having been once a plain, through which the valley of the stream has since been worn by the action of water; the upper stratum is a hard red sandstone, resting on a softer rock of a sandy or clayey character, beneath which the shales and rocks belonging to the coal formation show themselves, lying in unconformable beds, and often at a very high angle.  At 9.25 the stream divided into two branches, that to the east being the most considerable; at this spot the sandstone ceased, and we commenced ascending the granite range, the direction of which was about north-north-west.  The soil was poor and stony, producing a little feed for stock; but it could scarcely be made available, as the country is completely covered with thickets of acacia of small growth.  At 4 p.m. bivouacked on a small watercourse running through a level grassy flat, bounded on both sides by thickets of wattle.

Scrubby country north from the Irwin river.

19th September.

At 8.15 a.m. steered a nearly north course, through a country of the same description as yesterday; crossed several small gullies trending west, in some of which a little water still remained; at 4.20 p.m. halted for the night at a brackish pool in a small gully trending west.

20th September.

Started at 8.0 a.m., continuing a northerly course, over a similar description of country as during the past two days, crossing three large gullies coming from the eastward, but apparently near their source.  At 3.45 halted on a large stream-bed, with a few brackish or rather salt pools in its sandy channel, which was in some places nearly 100 yards wide; from our encampment we observed a very remarkable peaked hill, distant about twenty miles, and from its outline conjectured it to be composed of the same vein of trap-rock as that which forms similar ranges further to the eastward.

21st September.

The scarcity of water and the very level appearance of the country to the northward of our bivouac, added to the general denseness of the thicket of acacia and cypress, rendering a continuance of a north course unadvisable, we steered north-west from 8.30 a.m. till noon, when we ascended a scrubby sand ridge, from which we had an extensive view; neither hill nor valley could be discovered to the north, east, or west—­nothing but one immense sea of dense thicket of acacia and cypress was visible in these directions; the course was therefore changed to west, and continuing it without much alteration over a succession of low ridges of drifted sand, the valleys being filled with dense thickets,