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.