Thursday, July 24. Camel men long in starting; it was near seven before we were on our journey. Passed near several springs, and on the bank of one found some beautiful bog iron ore. The west side of the wadey had the appearance of a rugged sea coast, and the exposed ledges of rock, that of the beach washed by the waves. The rock is a fine grained sandstone, lying on aluminous slate, which mouldering into dust by exposure to the weather, undermines the sandstone, and gives rise to the rugged appearance. It is rendered more dreary and awful by the black colour of the external surface. At a distance we took the whole to be a basaltic formation, and were not a little deceived on our examination. We entered a narrow pass with lofty rugged hills on each side; some were peaked. The black colour of almost all with white streaks, gave them a sombre appearance. The external surface of this sandstone soon acquires a shining black like basalt: so much so, that I have several times been deceived, till I took up the specimen. The white part is from a shining white aluminous schistus, that separates into minute flakes like snow. The ground had in many places the appearance of being covered with snow. It blew a strong gale as we passed through the different windings; sand was tossed in every direction; the sky was sometimes obscured for several minutes. These, conjoined with the white of the ground and hills, brought forcibly to our minds a snow storm; but the hot wind as speedily convinced us of our error. The pass led to a valley, with a few tulloh trees; this we traversed, and soon entered on a large sandy plain, with the hills of Tadrart on the east, and the high sand hills on the west. This range has a most singular appearance; there is more of the picturesque in this, than in any hills we have ever seen. Let any one imagine ruinous cathedrals and castles; these we had in every position and of every form. It will not be astonishing, that an ignorant and superstitious people should associate these with something supernatural. That is the fact; some particular demon inhabits each. The cause of the appearance is the geological structure. In the distance, there is a hill more picturesque and higher than the others, called Gassur Janoun, or Devil’s Castle. Between it and the range, there is a pass through which our course lies. Hateeta dreads this hill, and has told us many strange stories of wonderful sights having been seen: these he firmly believes; and is struck with horror, when we tell him we will visit it.