From its head at the pass into Miti Kwan to its junction with Ibib, Wadi Soaorib has a length of about fifty kilometres. The level of the pass is unknown, but from Mitba to Ibib the level of the wadi floor falls from 505 metres above sea to 260 metres in a length of about forty-one kilometres, giving an average slope of six metres per kilometre. Most of the upper portions of Wadi Soaorib and its tributaries are well stocked with trees and bushes, but as the wadi crosses the sandy plain it becomes more and more barren. The place where it enters on the plain in latitude 22° 20′ marks a tribal boundary, the upper parts, including Wadi Dishlo, belonging to the Balgab Arabs, while the lower parts, including Wadis Eimya and Qidmib, are Kurbeilab territory. =Wadi Um Bishtit=, which joins Wadi Ibib some five kilometres lower down its course than does Wadi Soaorib, heads in a small open space in latitude 22° 26′ and longitude 35° 35′. At its head there are two easy passes, one leading northward into the head of Wadi Habliai, another tributary of Wadi Ibib, and the other southward into the heads of Wadi Meisah. Just below its head Wadi Um Bishtit is joined by the small =Wadi Delawet=, draining the hills close to the south; while a little lower down is another small tributary from a rocky gorge among the south hills, which is important as leading to =Bir Um Bishtit=. This well, which was filled by downwash when I visited it in March 1908, is situated in the floor of the gorge at a sharp bend, about a kilometre up from the main wadi. According to the guides, it requires excavating about five metres deep, and yields water in quantity for about a year after rain, but when there has been no rain for a year only small supplies can be got, as it fills slowly; at the time of my visit there was no necessity to open the well because there was plenty of water in galts in the mountains of Meis-heit-ar, a little further south. The well is easy of access, and lies at 330 metres above sea-level. The total length of Wadi Um Bishtit is about fourteen kilometres. In the first half of its course it runs north-westward, shut in by high hills, and contains abundance of small trees. After cutting through the hills it receives the Wadi Orgem from the south, and turns northward in opening country to join Wadi Ibib north of the hills called Adar Aweib Um Bishtit. Its average slope is about nine metres per kilometre. =Wadi Orgem=, which joins Wadi Um Bishtit about four kilometres below the gorge containing the well, has its head at an easy pass near the remarkable peak of O Shakafa; this pass leads into Wadi Meisah, about three kilometres above Bir Meisah. From the pass, the Wadi Orgem runs between the high hill ranges of Orgem and Um Bishtit, in a direction a little west of north, for about sixteen kilometres to its junction with Wadi Um Bishtit.