The Jibel Gulat is one of the highest hills we have yet come to. It is about six hundred feet high: its top is tabular, and its sides exceedingly rugged, from an amazing number of detached pieces. The lowest exposed stratum is a calcareous tufa, containing, or indeed almost formed of sea-shells; the most abundant are a species of oyster and limpet, in a very entire state. Above, beds of soft carbonate of lime, like whiting, and falling into dust on the slightest touch, and in which is imbedded a large quantity of lamellar calcareous spar. Above, and apparently extending to the summit, tolerably fine marble. The quantity of debris, and the size and appearance of the masses, might make one believe that an earthquake had been the cause of that rent state; but it appears to me more probable that the undermining, by the mouldering of the soft stratum underneath, accounts well for the state and appearance of the side of the hill. The hill is about three miles long, and runs from east to west. It is inhabited by a solitary family; a man, his wife, and several children. We were told that he had resided in this dreary and barren place for eleven years, and it is said lives chiefly by plunder. Near Niffud, the hills are of lime, and in structure and form not unlike those of the Tarhona range. In the vicinity of the long range there are a number of small conical hills, of a soft whiting-like substance, appearing as if recently thrown up, although, from every thing around, that is not at all probable. The range runs parallel to that near the coast; but we had no opportunity of determining how far it extends to the eastward and westward. There are several passes, into one of which we entered. It is rugged, from the number of masses that have fallen from the sides of the hills. Several tumuli of stones are observable, marking the burial-places of unfortunate travellers, who have been murdered here, it was said, by large rocks rolled from the overhanging heights. When I was examining the rocks, in the dry bed of a river, these monuments were pointed out, to make me aware my presence there was not free from danger. This led to a valley, with some thick groves of acacias, and a plant like a mespilus, with pleasant small astringent berries: it is called by the natives butomo. From this we passed over a low hill, into the valley Niffud. This valley has been the seat of much fighting, as our conductors informed us, among the Arabs of different tribes.