The higher mountains of the Eastern Desert generally form the watershed between the Nile and the Red Sea. This watershed is much nearer to the coast than to the Nile, with the result that the eastward drainage is much steeper than to the west.
Commencing from the north (see the orographical map, [Plate I]), the principal mountain masses are:—
(i) The Migif — Hafafit — Nugrus — Hangalia — Zabara group (1,505 metres[34]), cut off to the south by the Wadi Gemal (Fd).
(ii) The Abu Hamamid — Hamata — Abu Gurdi group (1,978 metres), limited on the south by the Wadi Lahami (Hg).
(iii) The Um Gunud — Dahanib — Batoga group (1,270 metres), lying between Wadi Lahami on the north and Wadi Khoda (Hj) on the south.
(iv) The Abu Dahr — Orga — Um Tenedba group (1,131 metres), separating the drainage of Wadi Betan (Fl) from Wadis Khoda and Rahaba (Hl).
(v) The Faraid group, the Mons Pentadactylus of Ptolemy, comprising some very remarkable granite peaks (1,366 metres), lying near the coast between Wadi Khoda and Wadi Rahaba.
(vi) The Awamtib — Abraq — Dif — Aqab el Negum — Mishbih group (1,353 metres), forming the tripartite watershed between the great Wadi systems of Kharit and Alaqi on the west, and that of Wadi Hodein on the east.
(vii) The Gerf — Abu Hodeid group, a mighty mass rising to 1,736 metres, lying between Wadi Hodein (Jn) and Wadi Hasium (Hs).
(viii) The Meisah — Adar Qaqa — Is group, between the Wadis Hasium and Di-ib (Mr).