Some of the mountains, especially the granite “bodkin” of Gebel Faraid (_Hl_), and some of the peaks of the Elba group, appear to be unclimbable. A few others are rather dangerous of ascent, as, for example, Gebel Abu Hamamid (_Ef_) on account of its steepness, and Gebel Abu Dahr (_Gk_) by reason of combined steepness and rotten rock, which comes away in tons at a touch. The highest peak of all within the district, Gebel Hamata (_Gf_), is a comparatively easy climb from the north. =Hydrography.= The course of the main watershed which parts the Red Sea and Nile drainages is highly irregular both in altitude and direction, as will be evident from the orographical map (Plate I), on which it is shown by a red line. From Gebel Hamrat Wogud, in the north, it passes east of Gebel Atut, thence through the high masses of Gebels Hangalia, Nugrus, Hafafit, and Migif, beyond which it drops southward through the low country round Gebel Abu Had. Entering the mountains again at Gebel Nukheira, it takes an eastward bend, passing along the great ridges of Gebels Abu Hamamid, Um Usher, Um Hasidok, and Ras el Kharit. Striking southward across the head of Wadi Kharit, it courses through the mountains of Mikbi and Abu Gurdi, thence dropping to the south on the plain near the hills called Marwot Elemikan. Turning here sharply westward over the plain, it passes through the hill-mass of Gebel Abu Derega and on to Gebel Zergat Naam, south-west of which it crosses the low tract at the head of Wadi el Arned to the sandstone plateaux of Dagalai, whence it courses a little to the west of Gebel Um Reit and enters the mountainous tract of Gebel Aqab el Negum. Its further course has not been traced in detail, but from guides’ statements and the indications of the main drainage-lines it is believed to run as shown on the map, in a great curve through the two sharp peaks of Gebel Sheyenit to the west of Gebel Mishbih, and then in another flatter curve south-eastwards to Gebel Soaorib, at the head of Wadi Hasium. Continuing along the mountain ridges of Gebel Soaorib, it crosses to Gebel Is,[36] separating the Wadi Is from the heads of Wadi Alaqi on the Sudan frontier. The watershed is for a great part of its course quite impassable for camels. The principal places where it can be crossed are at the head of Wadi Nugrus, near Abu Had, the Wadi Marasan between Huluz and Wadi el Sheikh, the heads of Wadi Lahami, Wadi el Fil, Wadi Arned, and Wadi Um Reit, passes at Aqab el Negum and Hamrat el Feg, near Gebel Mishbih, the head of Wadi Hasium, and the pass of Adar Ameit, north of Gebel Is. All these places are practicable for baggage camels, though in some of them, as, for instance, at the head of Wadi Nugrus, care is required because the track is steep and stony.