Saturday, 28th April, Gum Creek under Mount Denison. As soon as the horses were caught I started for the top of the mount. I left my horse in a small rocky gum creek which I thought would lead me to the foot of the mount. At about a quarter of a mile from the mouth of the gorge, I came upon some water in a rocky hole, followed it up, and, two hundred yards further, was stopped by a perpendicular precipice with water trickling over it into a large reservoir. I had now to take to the hills, which were very rough, and after a deal of difficulty I arrived, as I thought, at the top, but to my disappointment I had to go down a fearfully steep gully. At it I went, and again I arrived, as I fancied, at the top, but here again was another gully to cross, and a rise still higher. I have at last arrived at the summit, after a deal of labour and many scratches. This is certainly the highest mountain I have yet ascended; it has taken me full three hours to get to the summit. The view is extensive, but not encouraging. Central Mount Stuart bears 95 degrees. Mount Leichardt, 155 degrees 30 minutes. To the south, broken ranges with wooded plains before them, and in the far distance, scarcely visible, appears to be a very high mountain, a long, long way off. To the south-west the same description of range. About thirty miles to the west is a high mount with open country, and patches of woodland in the foreground. At the north-west there appears to be an immense open plain with patches of wood. To the north is another plain becoming more wooded to the north-east. As this is the highest mountain that I have seen in Central Australia, I have taken the liberty of naming it Mount Denison, after his Excellency Sir William Denison, K.C.B., Governor-General. The next range (bearing 334 degrees), being the last of the highest ones north, I have named Mount Barkly, after his Excellency Sir Henry Barkly, Governor-in-Chief of Victoria. When on the second highest point of this mount, I saw a native smoke rise up in the creek below, a short distance from where I had tied my horse. This naturally made me very anxious for his safety, and when I descended I was rejoiced to find him safe. The natives have been in the creek and on the mount: their tracks, which are quite fresh, lead me to conclude that they have been running. The descent was difficult, but I discovered a shorter route, and it has taken me two hours to come down. Arrived at the camp at 4.30, and found all right. I intended to have built a large cone of stones on the summit; but, when I arrived there, I was too much exhausted to do so. I have, however, erected a small one, placing a little paper below one of the stones, to show that a white man has been there. I have also marked a tree "J. M.D. S." on the creek where we are now camped. Mount Denison bears from here 249 degrees.