_Tuesday, August 6._—The sand-hills which we ascended after starting were not very high, but after a while we had to make another ascent. Sometimes small ridges of quartzose sandstone, setting right across our path, at others ethel-bushes, gave a little variety to the waste, and at the distance of about eight miles from the well singularly shaped conical mounts began to rise. The eastern road, which is a little more circuitous, is but a few hours’ distance from this; it leads through a valley at the foot of a high conical mount, with temporary ponds of rain-water, and herbage called Shambakésa, which about noon we passed at some distance on our left. In the afternoon we came in sight of a continuous range of heights ahead of us. The whole region exhibited an interesting intermixture of granite and sandstone formation, white and red sandstone protruding in several places, and the ground being strewn with fragments of granite and gneiss. Passing at one time over gravel, at another over rocky ground strewn with pebbles, we encamped at length in a sort of shallow valley called Taghárebén, on the north side of a very remarkable mass of curiously shaped sandstone blocks, heaped together in the most singular manner, and rising altogether to a height of about one hundred and fifty feet. On inspecting it more closely, I found that it consisted of four distinct buttresses, between which large masses of loose sand had collected, the sandstone being of a beautiful white colour, and in a state of the utmost disintegration. After a weary day’s march, the camping-ground, adorned as it was with some fine talha-trees, and surrounded with small ridges and detached masses of rock, on which now depended the beauty of the scene, cheered our minds, and fitted us for another long day’s work. Soon after we started the ground became rugged and stony, and full of ridges of sandstone, bristling with small points and peaks. In this wild and rugged ground our people amused themselves and us with hunting down a lizard, which tried to escape from the hands of its pursuers in the crevices of the rocky buttresses. Then followed broad, shallow valleys, at times overgrown with a little herbage, but generally very barren; winding along them we turned round a larger cluster of heights which seemed to obstruct our route. Bare and desolate as the country appears, it is covered, as well as the whole centre of the desert, with large herds of wild oxen (_Antilope bubalis_), which rove about at large, and, according as they are more or less hunted, linger in favoured districts or change their haunts. Our men tried to catch them, but were unsuccessful, the animal, clumsy and sluggish as it appears, climbing the rocks with much more ease than men unaccustomed to this sort of sport, and, owing to the ruggedness of the ground, being soon lost sight of.