328 



GEOGRAPHICAL PROGRESS AND DISCOVERY. 



of the river had been previously given by a 

 slave, and the abb6 places full faith in it. Lieu- 

 tenant-Colonel Godwin-Austen, who in the 

 campaign against the Daflas, made some valu- 

 able geographical observations in the Eastern 

 Himalayas, thought that he sighted the course 

 of the Tsangpo or Brahmaputra. From mounts 

 Tornputu (7,300 feet) and Shengarh (6,700 

 feet), in the farther Himalayan chain, he could 

 follow with his eyes the main valley toward 

 the north. The northwest branch of the val- 

 ley of the Subansiri river (latitude 28 K, lon- 

 gitude 93 E. of Greenwich), rises among the 

 group of snowy peaks (23,000 feet) which are 

 seen from Tezpur, in Assam ; while a second 

 deep break in the mountains lies east of the 94th 

 meridian, which runs into the northwest val- 

 ley in about 27 40' N. latitude. This northwest 

 arm Colonel Godwin-Austen thinks is the fork 

 which the Pundit Nain Singh crossed on his 

 way from Lhasa to Tansang, and the other 

 branch he holds for the Tsangpo. His grounds 

 for considering the Subansiri as the upper 

 course of the Brahmaputra, rather than the 

 Lohit or the Dihong river, are summed up as 

 follows : the temperature of the Subansiri at 

 its junction with the Brahmaputra is lower 

 than that of any other stream ; Lieutenant 

 Harman judged it to be the largest tributary, 

 and found that the mountaineers considered it 

 identical with the Tsangpo ; the Tsangpo's 

 course, as it was observed by Nain Singh, lay 

 in the direction of the Subansiri. 



Dr. Schweinfurth made a trip through the 

 mountain region between the Nile and the 

 Red Sea, which, partly owing to the jealous 

 fears of the Egyptian Government, has never 

 been explored to any purpose before. In a 56 

 days' journey, starting the 24th of March from 

 Heluan below Cairo, he surveyed and mapped 

 a considerable portion of this tract, with special 

 reference to its geological character : his sur- 

 vey embraced that part of the Arabian desert 

 which lies between Cairo and Keneh. Leav- 

 ing Heluan he crossed an eocene* limestone 

 plateau and several wadis to the mouth of the 

 southern wadi As-Khar, which leads up to the 

 southern Hamada (4,100 feet) : this wadi As- 

 Khar is distinguished among all the valleys of 

 the Arabian desert by its rich vegetation, em- 

 bracing many species of the flora of Palestine, 

 which are found nowhere else in Egpyt ; it is 

 bordered, like the northern wadi As-Khar, by 

 picturesque cliffs of the nummulitic plateau. 

 Mount Sinai, across the gulf of Suez, is the con- 

 necting link between this plateau and Pales- 

 tine. He visited the monastery St. Antonius, 

 and crossed the mountains to the monastery of 

 St. Paul (1,290 feet), which lies at the foot of 

 a precipice of 3,940 feet, to which the beauti- 

 ful wadi Rigbe (" the path ") leads down. 

 This wadi shows the traces of glacial action in 

 remarkable accumulations ~vf^Mbris, forming 

 perpendicular walls along the bed of the torrent; 

 the pistachio tree grows wild here. The water 

 divide between the Nile and the Red Sea is an 



important geological boundary, where the por- 

 phyry and hornblende rocks meet the sand- 

 stone formation which underlies the middle 

 chalk and nummulitic limestone beds, which 

 latter crop out at the base of the great plateau. 

 In the chalk-beds of the wadi Mor he picked up 

 new species of ammonites of unusual size. 

 Across the line of contact between crystalline) 

 and sedimentary rocks, he crossed a barren 

 plateau, south of wadi Hauashieh, and passed 

 Gebel Gharib or Raghib ("the isolated") 

 which is the highest point undoubtedly of the 

 porphyry chain, and probably of all Egypt, and 

 whose solitary mass culminates in a dozen coni- 

 cal peaks to Gebel Mangul, and along the east- 

 ern slope of the central range, where he passed 

 a large number of peaks of over 5,000 feet alti- 

 tude, to wadi Abu Sidr, which extends from 

 Gebel el-Dukhan (th e an cient Porphy 'rites Mons) 

 to the sea. The Sidr trees (Zizyphus Spina, 

 Christi), which give the name to the valley, 

 grow wild near a Roman cistern, but are not 

 met with- elsewhere in Egypt ; above the trees, 

 on the northwestern slope of the mountain, 

 are the famous porphyry quarries ; on the west- 

 ern side of the valley are the ruins of a Roman 

 town and a temple. The Roman road from 

 the quarries to the seaside is still practicable 

 for carriages. East of Gebel Gattar is a re- 

 markable serrated group of mountains, whose 

 conical summits succeed each other like the 

 ribs in a fish-bone. Along the old porphyry 

 roads are the ruins of three other Roman set- 

 tlements, which contain enormous cisterns of 

 massive masonry. As rain had not fallen in 

 this region for five or six years it was devoid ' 

 of all vegetation except acacias. Schweinfurth, 

 in his journey, found that the western boundary 

 of the nummulitic plateau was a line drawn 

 from Keneh to Suez. The eocene limestone 

 hills do not extend far to the south of Keneh, 

 nor far to the east. To the north of the town 

 the plateau is intersected by the wadi Keneh, 

 which is the largest in Egypt, and is separated 

 by a low ridge from wadi Hauashieh. ev- 

 eral wadis descend to wadi Keneh from the 

 eastern border of the plateau. Wadi Tarfeh 

 is the only other wadi which crosses the plain 

 from west to east, and this is formed from the 

 union of five small valleys. 



Captain Roudaire in his laborious and haz- 

 ardous survey of the great depression in Tu- 

 nisia and Algeria, in 1875 and 1876, ascer- 

 tained that the region lying below the low-tide 

 mark of the Mediterranean, and capable of in- 

 undation, has a length of about 400 kilometres. 

 The Algerian depression of Mel'rir occupies a 

 surface of about 6,700 square kilometres ; and 

 the Tunisian depression, occupied by the chotts 

 El Fejej, Djerid, and Rharsa, covers about 

 10,000 square kilometres. These chotts, called by 

 that name in Arabic, but named sebTcaJis by the 

 Tunisians, are level and utterly devoid of vege- 

 tation. The bed of the Djerid chott is occupied 

 by a strange body of water of unknown depth, 

 covered by a salt crust, _whose thickness is only 



