The next feeder of Wadi Huluz, called Wadi Mahali, enters from the south, its head being on the main watershed between Gebels Um Usher and Um Hasidok. Passing between Gebels Um Usher and Um Laham, the Wadi Huluz receives Wadi Tarfawi, draining the mountain of the same name from the east. Further down, feeders come in from Gebel el Mehali on the south and from the high hills south of Gebel Um Heshenib on the north. Near the meridian of 34° 50′ two important tributaries enter Huluz near together from the south. The upper one, Wadi Hilgit lil Huluz, heads in a very steep and difficult pass, leading into Wadi Hilgit lil Kharit. The lower one, called Wadi Um Semiuki, drains the north-east flanks of Gebel Abu Hamamid. Nearly opposite the mouth of Wadi Um Semiuki is another feeder of Wadi Huluz, which I believe forms the main drainage channel for the south face of Gebel Um Heshenib; but it is said to be very steep and stony, and my Arabs preferred to reach Gebel Um Heshenib by a small wadi, containing several tombs, some four kilometres higher up Wadi Huluz, whence there is a stony pass leading into the above-mentioned main drainage channel at a point above the obstructions in it.
About eight kilometres further on, on the north-east side of the wadi, there is a low gap over which by a very easy pass one can descend into the head of Wadi Durunkat, leading to Wadi Gemal. Some three kilometres lower down, Huluz receives two tributaries together; one, from the south-east, is called Wadi Um Hegiligi lil Huluz, while the other, from the south-west, is called Wadi Marasan and heads in an easy pass on the main watershed, over which a track leads south-east and south to the well and tomb of Sheikh Shadli.
Two sheikhs’ tombs and some smaller graves exist at a bend in the Wadi Huluz, three kilometres below the point of influx of Wadi Marasan. Below these enter as feeders Wadi Um Suerab lil Huluz from the north, and Wadi Abu Gerifat from the south. The wadi now becomes very tortuous. Near the meridian of 34° 40′, on the south side of the wadi, at a bend where trees are very abundant, is a small gully containing the important water holes called Um Gerifat. These are rock basins fed by rain water draining down steep gorges from the hills round the twin-peaked Gebel Um Sedri; they are easily accessible in a few minutes from the main wadi, and contained good supplies of water in the winter of 1905-1906. About four kilometres lower down, the Wadi Um Iteili enters from the east, and about five kilometres beyond this Huluz opens out into a somewhat triangular space, when the Wadi Gaetri enters from the west and Wadi el Khisei from the east. The Wadi Gaetri leads by an important pass into the more open country to the west (wells of Wadi Khashab and Wadi Natash).
At the open space above-mentioned, Wadi Huluz turns northward, winding somewhat, for some eight kilometres, and then, after receiving the Wadi Abu Etl as a feeder from the west, turns sharply eastward and becomes the Wadi Gemal.
Wadi Durunkat, a tributary of Wadi Gemal, forms an important road from Wadi Gemal into the higher parts of Huluz. By following it up to its head about twenty kilometres from its junction with Wadi Gemal, one can enter Wadi Huluz by a very easy pass in longitude 34° 46′, thus cutting off the long winding course of Wadi Huluz itself; and from this pass one can cross the main watershed by the Wadi Marasan to reach Bir Shadli.
Wadi Hafafit, another tributary of Wadi Gemal, has its head situated close to the east side of Gebel Migif, in latitude 24° 50′, on the main watershed, where there is an easy pass into the head of Wadi Shait. Following a very straight course for nearly forty kilometres south-east, with the remarkable range of high gneiss mountains called Gebel Hafafit on the left, and the sugar loaf granite hills of Abu Had on the right, Wadi Hafafit forms a broad barren valley in which there are heavy accumulations of blown sand. Wadi Abu Had, a small western feeder of Hafafit, is well known by reason of the well of bitter water, Bir Abu Had, at its head. An eastern feeder of Wadi Hafafit, which joins it shortly before the junction with Wadi Gemal, is called by the diminutive name of Wadi Hefeifit.
Wadi el Abiad, likewise a tributary of Wadi Gemal, derives its name from the coarse white granitic sand which forms its floor. Its heads are situated near latitude 24° 20′, among the granite mountains called Gebel el Abiad and on the northerly slopes of Gebel Um Heshenib. There is a very steep pass from its head, east of Gebel Um Heshenib, into Wadi Huluz. Pursuing an almost northerly course and falling rather rapidly, Wadi el Abiad is at first very wide, with high granite hills on each side. It narrows further down, at a point opposite Gebel Shoab, where a small eastern feeder leads by an easy sandy pass into the Wadi Shoab. A little lower down, passing into diorite country, it turns more to the east, and after receiving the Wadis Um Seyal el Foqani and el Tahtani from the south-east, enters the Wadi Gemal near Madaret Um Gamil. The wadis called Um Seyal receive their name from the abundance of acacia trees in them; at the head of Wadi Um Seyal el Foqani there is a pass leading by the Wadai el Anz into Wadi Um el Abbas.
Wadi Nugrus, an important tributary of Wadi Gemal, commences its course on the main watershed west of Gebel Nugrus, in latitude 24° 48′, at the pass into Wadi Gerf, 690 metres above sea-level, and courses south-east in almost a straight line for nearly forty kilometres to join the Wadi Gemal in latitude 24° 34′ and longitude 34° 50′. The fall to this point is some 450 metres, or an average of over ten metres per kilometre, but the fall is most rapid near the head, where the floor of the wadi is rocky and steep; the slope for the first few kilometres is over double the average.
The approach to the head of Wadi Nugrus from the north, by one of the heads of Wadi Gerf, is almost a plain. But as soon as Wadi Nugrus is entered one becomes very sensible of the greater steepness of the eastern drainage by the stony nature of the track and the rapid fall. The wadi here is in fact only a narrow gorge with the huge mountains of Hafafit and Nugrus on the west and east sides respectively. Some three kilometres below the pass, close to the west side of the wadi, in a narrow gorge, is the spring called Megal el Harami, situated in gneiss rocks, and giving supplies of good water; the water infiltrates slowly, however, so that the yield is not sufficiently rapid to supply large quantities at once. Lower down, the wadi broadens out considerably, with a sandy floor in the middle of which low dark hills rise like islands. About thirteen kilometres below the head, an important feeder, the Wadai el Nom, comes in from the north-east. This wadi drains the south-east flanks of Gebel Nugrus and the west flanks of Gebel Hangalia; it contains rock basins holding water for some time after rain, and leads to a steep winding pass which enables one to make a circuit round the great granite mountain of Gebel Nugrus. The pass is, however, impracticable for baggage camels, and one has to dismount from a riding camel in order to get over.
Beyond the junction of Wadai el Nom, the Wadi Nugrus continues its straight course south-east, between the long range of Gebel Hafafit on the west and Gebel Zabara on the east. Some thirty kilometres below its head, Wadi Nugrus receives the Wadi Abu Rusheid from the north, and a little further on one encounters on the east the ruins of an old village called Medina Nugrus. Just opposite the ruins is a small feeder called Wadi Abu Sada, a short distance up which are rock basins yielding water after rain, but these were dry in 1905. Not far below this, there are some old workings in a small feeder on the east side of the Wadi Nugrus, six kilometres above its junction with Wadi Gemal.