July 17.--To-day we returned to our temporary camp, tracing up various branches of the water-courses as we went along, but without finding water. Many of the ranges in our route consisted of masses of ironstone, apparently containing a very large proportion of metal. In one place, I found a mineral which I took to be tin ore; the loss, however, of all the geological specimens I collected, after their arrival in Adelaide, has unfortunately put it now beyond my power to test any of the rocks or minerals, about which I was doubtful. As we encamped early, and I was desirous of recruiting the horses, I employed myself in taking an observation for latitude, whilst the black boy went out to look for an opossum. He succeeded in bringing in a fine large one, which formed a welcome addition to our meagre fare. The nights were still very frosty. July 18.--In travelling to "Depot Pool," the native boy caught another opossum, and we again halted early in the day for the sake of resting the horses. July 19.--Concealing among some rocks every thing we did not absolutely require, we descended towards the plains, searching as we went, for the most favourable line of road to them, for the drays, but at best the country was very rough and stony. After clearing the hills, we made a stage of twenty-eight miles along the plains running under Flinders range, and at night encamped upon a channel coming out of it, where we obtained water, but very little grass for our horses. July 20.--To-day I kept behind some of the low front hills, passing through some extensive valleys between them and the main range; and as I found abundance of water lying in pools upon the plains, I did not make for the hills at all. Before sunset, I got a shot at a kangaroo with my rifle, which, though severely wounded, gave me a long chase before I could capture it; this furnished us with a welcome and luxurious repast. We had been so long living upon nothing but the bush baked bread, called damper (so named, I imagine, from its heavy, sodden character), with the exception of the one or two occasions upon which the native boy had added an opossum to our fare, that we were delighted to obtain a supply of animal food for a change; and the boy, to shew how he appreciated our good luck, ate several pounds of it for his supper. Our horses were equally fortunate with ourselves, for we obtained both good grass and water for them. July 21.--Taking with us the best part of what was left of the kangaroo, we crossed a stony ridge to the S. W., and at four miles struck a watercourse with a large pool of water in its bed, and well adapted for a halting place for the party on their route to the north: we had not seen this in our outward course, having kept further to the westward in the plains. From the water-hole, Mount Eyre bore W. 30 degrees S. distant five miles.