The principal heads of Wadi Huluz are close to the south-east of Gebel Hamata, in a _cul-de-sac_ formed by the high mountains of Gebel Hamata (1,978 metres above sea) and Gebel Ras el Kharit (1,661 metres). Here a number of steep gorges unite to form the main channel, which due south of Hamata has an altitude of 1,053 metres above sea-level. Following a winding course among the mountains as a rapidly falling valley with a sandy floor averaging 100 metres or more in width, it passes west of the great mass of Hamata, receiving the drainages from the north-east flanks of that mountain and from the north face of Gebel Um Hasidok. At its crossing the meridian of 35° it receives as a feeder the =Wadi el Abiad lil Huluz=, which drains the north face of Hamata and the south flanks of Gebel Abu Ghusun; draining mostly from granite country, this feeder has a floor of coarse granitic sand, from the whitish colour of which it takes its name. 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.