In these scrubs are met nests of the building rat (Mus conditor). They form their nests with twigs and sticks to the height of four feet, the circumference being fifteen to twenty. The sticks are all lengths up to three feet, and up to an inch in diameter. Inside are chambers and galleries, while in the ground underneath are tunnels, which are carried to some distance from their citadel. They occur in many parts of Australia, and are occasionally met with on plains where few trees can be found. As a general rule, they frequent the country inhabited by the black oak (casuarina). They can live without water, but, at times, build so near a watercourse as to have their structures swept away by floods. Their flesh is very good eating. In ten miles we had passed several little gullies, and reached the foot of other hills, where a few Australian pines were scattered here and there. These hills have a glistening, sheening, laminated appearance, caused by the vast quantities of mica which abounds in them. Their sides are furrowed and corrugated, and their upper portions almost bare rock. Time was lost here in unsuccessful searches for water, and we departed to another range, four or five miles farther on, and apparently higher; therefore perhaps more likely to supply us with water. Mr. Carmichael and I ascended the range, and found it to be 900 feet from its base; but in all its gullies water there was none. The view from the summit was just such as I have described before--an ocean of scrubs, with isolated hills or ranges appearing like islands in most directions. Our horses had been already twenty-four hours without water. I wanted to reach the far range to the west, but it was useless to push all the pack-horses farther into such an ocean of scrubs, as our rate of progress in them was so terribly slow. I decided to return to the small supply I had left as a reserve, and go myself to the far range, which was yet some thirty miles away. The country southward seemed to have been more recently visited by the natives than upon our line of march, which perhaps was not to be wondered at, as what could they get to live on out of such a region as we had got into? Probably forty or fifty miles to the south, over the tops of some low ridges, we saw the ascending smoke of spinifex fires, still attended to by the natives; and in the neighbourhood, no doubt, they had some watering places. On our retreat we travelled round the northern face of the hills, upon whose south side we had arrived, in hopes of finding some place having water, where I might form a depot for a few days. By night we could find none, and had to encamp without, either for ourselves or our horses.