[Footnote 30: In my paper on ‘Recent Determinations of Geographical Positions in the Libyan Desert,’ published in Cairo in 1919, I gave (p. 14) the approximate position of the hill as lat. 24° 28′, long. 27° 45′. The position given above is from a more accurate determination which I made on revisiting the place with Prince Kemal el Din in 1923. On this latter occasion the excavations made by the Prince in the sand around the foot of the hill revealed the existence of hundreds of additional jars, many of them intact, set in regular order in the sand and obviously forming a water-dump. The majority of the jars bore clearly incised markings, which Prince Kemal el Din was able later to identify positively as being tribal marks of the Tebus, the marks being in fact exactly the same as those used by the Tebu tribes of the present day.] [Footnote 31: See Jordan’s ‘Physische Geographie und Meteorologie der libyschen Wüste’ (Cassel, 1876), p. 215.] [Footnote 32: ‘Kharga Oasis’ (Cairo, 1900), p. 57.] [Footnote 33: _Geogr. Journ._, 42 (1913), p. 283; also ‘Mysteries of the Libyan Desert’ (London, 1925), p. 304.] [Footnote 34: This “locus” is of course given by joining up the points of intersection of the 100-metre water-contour with the 200-metre ground-contour, the 200-metre water-contour with the 300-metre ground- contour, and so on.] [Footnote 35: It is possible that the “Nubian Sandstone” in South- Western Egypt may represent more than one geological system, as has been found to be the case in Sinai. Col. Tilho (_Geogr. Journ._, 56 (1920), p. 259) records that the sandstone at Ennedi proved to be of Upper Silurian age by the fossils found in it.] [Footnote 36: Though we passed within 10 kilometres to the east of Kissu on the return journey from Merga to Owenat in 1925, I could not observe the structure of the mountain very clearly, owing to haze. But it appeared to me to be a huge granitic intrusion rising through the gneiss which covers a large area hereabouts. The sandstone over which we had been travelling since leaving Merga gave place to gneiss about 40 kilometres before we came abreast of Kissu, and gneiss continued to be the country rock until we came within 30 kilometres of Gebel Owenat, when sandstone reappeared, at first capping low hills and then forming the plain.] [Footnote 37: There exists no published English translation of Ptolemy’s ‘Geographia.’ Müller’s edition (Paris, 1883-1901) gives Greek and Latin texts, with a Latin commentary.] [Footnote 38: Quoted in Müller’s edition of Ptolemy’s Geography, p. 739.] [Footnote 39: For the latest delineation of this region, see the hypsometric map in the ‘Atlas de l’Algérie et de Tunisie,’ published by the Cartographic Service of the Algerian Government, Paris, 1924, Fascicule II.] [Footnote 40: ‘Manual of Ancient Geography’ (London, 1891), p. 311.] [Footnote 41: _Geogr. Journ._, 56 (1920), p. 94.] [Footnote 42: ‘Mysteries of the Libyan Desert’ (London, 1925), p. 303.]