Having remained eight days at Siwah; on the 29th of September, at three in the afternoon, we broke up our encampment, and proceeded a three hours march, when we again pitched our tents at foot of a hill. The next day we began our journey late, being delayed till one o’clock, in search of a slave who belonged to a court-officer of the Sultan of Fezzan, and who had absconded from the caravan. Whilst the man was looking for, I set out with a view of inspecting some catacombs which I descried on the neighbouring hills, but was stopped at some distance by a lake of seven or eight miles in circumference, formed at the base of the mountain by the conflux of springs and small pools of water, which the rains at this season had swollen and brought together. Returning to the camp, I took my telescope to examine the appearances I was not enabled closely to inspect, when the first object on the mountain which presented itself to my view was the Negro after whom the search was making. I gave no notice of my discovery, the poor fellow having a good character, and having been driven to the attempt of flight by the extreme severity of his master. I am sorry to say there was little hope of his final escape, the Siwahans having promised to deliver him up. This day we travelled till half an hour after sun-set. The next day we marched at two hours before day-break, and halted at nine. The fourth day brought us to the fruitful valley of _Schiacha_. The mountains by which we travelled from _Siwah_ to this spot, are branches of those which I have mentioned as appearing, at all times, to north of our way through the Desert, and often at but little distance. They rise abruptly, and as precipices, from the level ground, and shew a face of mere rock, without the least covering of soil or even of sand. Their appearance, taken together with that of the _sea-sand_ which covers the Desert, indicate this vast tract to have been flooded, and at a period later than the great deluge. In the sandy plain below these mountains is seen the surface of a vast calcareous rock, containing no substance of petrifaction, whereas the mountains near consist of limestone, crowded and filled with fragments of marine animals and shells. The strata of all these rocky hills lay horizontal.