376 GEOLOGICAL SYSTEM OF CENTRAL SAHARA, APP. II. in one, El Hamman, near El Outaia, where the water, which was slightly salt, and with an hepatic smell, had a temperature of 95° Fahr. In another hot spring near Biskra I found swarms of a little fish (Cyprinodon dispar.), which has been identified with those found in the warm springs of Egypt, enjoying themselves at a temperature of from 75° to 85° Fahr. NOTE.-Through the kindness of M. Josse, the engineer employed by the French Government in sinking the artesian wells of the Wed R'hir, I am enabled to give the particulars of the section of the bore at Tamerna. Mètres. 3.05 Vegetable soil. 40 Clay with gypsum. 20 Hard red clay. 1.75 Ditto, sandy. 67 Gypsum, sand, and clay. 7.63 Hard red clay, with gypsum. 3.97 Yellow clay. 1.01 Sand, wet, with a little fresh water rising. 3.89 Gypsum, earthy. 1.17 Red clay. 2.89 Sandy clay and gypsum. 3.80 Nodules of gypsum bedded in clay. 3.86 Fluid red sand. 58 Hard sandstone. 9.08 Red sand, more or less hard. 2.35 Yellow clay, with masses of rolled gravel. 69 Ferruginous red clay, with rolled pebbles. 8.37 Hard sandstone in detached masses. •80 White sand, with a jet of water rising to the surface at 60.00 APPENDIX III. ON THE HISTORY OF THE SAHARA. THE records of history afford few and indistinct glimpses of the changes and convulsions which have kept the Sahara in a state of chronic barbarism. The loss is not great; little interest and less profit can attach to the chronicles of tribes who, unimproved themselves, have never affected their neighbours save by some predatory inroads. Their submission to the Romans was never more than partial and temporary. The remains consequently of Roman occupation are very scanty, consisting chiefly of forts hastily thrown up during the pursuit of fugitive tribes. These are more evident in the eastern than in the western districts. None are known in the (French) Algerian Sahara beyond Djelfa. But in the Eastern Sahara, among the plains of the Djidi, roamed over by the Weled Naijl, at the destroyed and desolate oasis of Doussan (query, anciently Decenna?) are traces of Roman walls. On the banks of the Wed Djidi near this spot are a line of ruins of gates, which seem to mark the extreme point of Roman occupation, since no trace of ruins which can be with any reason ascribed to them has yet been discovered further south.* As we travel northwards from this point, at Volga, in the Ziban, are the faint traces of a Roman fort. Nothing further occurs to arrest the antiquarian till in the northeast portion of the Sahara, between the Wed Beitam and the Wed Barika, are the traces of the ancient and extensive city of Tubna, of which nothing remains above ground beyond the pavement of the citadel. Above El Outaia, a day's journey north of Biskra, are * See page 280. found ruins which attest their importance by an inscription now preserved in the wall of the modern caravanserai, proving the former existence of a theatre at this spot. The place was probably the Messarfilis of the itineraries, and derived its importance from the salt-quarries in the neighbourhood. Above this, at the confluence of the Wed Guebli and the Wed Lekhernin, in the oasis of El Kantara, are a few Roman ruins. In the gorge of El Kantara itself, the exact boundaryline of the Sahara, is the beautiful and well-preserved bridge of Roman construction, and on the left bank of the gorge among the rocks are the traces of a paved way, which in some places is still perfect. The only other Roman remains which we met with are on the road from Biskra to Zeribet el Wed, at Burdoun in the Zab Chergui, at Setif Zama, and again at the village of Thouda. The Romans appear to have had very little idea of the distinct races of the Sahara, but at first comprised the northern, or Numidians proper, with the southern and central, or Gætuli, under the common appellation of Numidians (vouάdes), which they subsequently confined to the tributaries of Carthage. Both these names were unknown to the natives themselves. It is curious to remark the very different traditions related by Sallust, of the country having been settled from Spain, and the later one of Leo Africanus, that the wandering tribes derived their origin from the fertile coast region of Tunis. The first distinct mention of the Saharan tribes occurs in the reign of Valentinian, A.D. 373; when the oppressed provincials rose under Firmus against the tyranny of Count Romanus. The unfortunate Theodosius, after landing at Gigeli with a small force, penetrated the Atlas, and completely routed Firmus, who fled to the Sahara, and was received by Igmazen, King of the Isaflenses. Although Ammianus Mar. tells us that Firmus fled as far as the land of dates and the borders of the deserts, we cannot place the Isaflenses south of Djelfa; and as far as the indistinct record of Ammian can be understood, Igmazen ruled over the country from Medeah to Laghouat, residing somewhere in the Djebel Sahari. So completely had the imperial authority been lost beyond the Atlas, that we are told the savage inhabitants had forgotten the very name of Roman. Igmazen, repeatedly defeated by Theodosius, at length consented to deliver up his guest, who, however, anticipated the vengeance of his conquerors by strangling himself in the night. His dead body was surrendered by Igmazen, and Theodosius returned in triumph to Setif. It was probably during this campaign that the fortified camps near Djelfa were thrown up. (Ammian, xxix. 5; Gibbon, ch. XXV.) We have no proof that Christianity, however successful in the north, was ever accepted by the Gætulians of the south, for the Beni M'zab, who confess to having embraced the Gospel, were at that time inhabitants of the Tell. On the contrary, Procopius (vol. i., p. 334, ed. Bonn) tells us they readily united with Genseric in his attacks upon their Christian suzerains, A.D. 429, and committed atrocities which rivalled those of their barbarian allies. But with the usual fickleness of such tribes, they soon became dissatisfied with the Vandals, and rendered considerable assistance to their old enemies the Mauri in recovering part of the conquests of Genseric from Thrasamund his second successor. Belisarius in his most successful expedition never penetrated beyond the Tell; and Numidia and Gætulia disappear from history, until the Arabs under Akbah or Okbah ben Nafi, lieutenant of the Khalif Moawiyah, after the conquest of Egypt, advanced to the westward by a hitherto untrodden route. By the aid of their camels, now first introduced into Africa, they penetrated behind the colonies of Cyrenaica and Tripoli, and, emerging to the south of Tunis, in A.D. 665 took possession of Gætulia before they thence established themselves on the littoral. Okbah, whose name is still consecrated by many a mara bout or cenotaph erected on the spots where he halted in the Sahara, performed a feat never since achieved, and traversed the country until he caught sight of the Atlantic. (Gibbon, ch. li.) After the defeat and death of Okbah the tide of Arab invasion fell back for a time. The triumphs of the Berber Queen, Cahina, were but of short duration; and Hassan, the Governor of Egypt, and his successor Musa, more permanently established the supremacy of the Khalifs in the Sahara as well as on the Atlas. For several centuries we hear nothing more of the country, till, during the Saracen dissensions in Spain, the Berber chief, Youssef ben Tachfin, in A.D. 1026, consolidated an independent power in Gætulia. His tribe, the Zenaga, though they professed the Moslem faith, were, in the opinion even of their rude neighbours, barbarous and uncivilized. They were enlightened by the zeal of their apostle, Abdallah ben Yussu, who named them, from their religious ardour, El Merabith. By the aid of their fanaticism Abdallah established a Berber empire throughout the whole south, under his dynasty, known afterwards by the name of the Almohades. From this epoch the lengthy native chronicles, many of which have recently been translated or epitomized by the French Orientalists, furnish a weary record of intestine dissensions until the time of Barbarossa, A.D. 1500. After that period the western tribes, including those between Laghouat and Waregla, vacillated in their allegiance between Algiers and Morocco, both of whom made occasional incursions into the interior. The northern tribes acknowledged the Bey of Tittery, while the eastern and most populous portion paid a fitful tribute to the Bey of Constantine, when he seemed strong enough to be able to exact it; and the Djereed or Tunisian Sahara yielded a steady obedience to the less capricious sway of the Beys of Tunis. In 1844 the French first visited the western Sahara, when Laghouat submitted to an impost of 30,000 francs. In 1852, the tribes having reasserted their independence, |