side, or depressed on the west — a view which can be demonstrated at many points by a comparison of the strata along the opposite sides of the valley. Thus at the saddle of er-Kishy, above referred to, we find the Cretaceous limestone forming the clitl's on the west side of the valley, while on the opposite side the Edomite cllll's are composed of masses of granite, porphj'ry, and schist surmounted by the Nubian sandstone, which is in turn over- lain above Petra, at a level of about 4000 ft., by the same Cretaceous limestone of er-Rishy ; being very nearly the amount of the vertical dis-
filacement of the strata which occurs along the ine of fault at this spot. Somewhat similar are the relations of the rocks at the southern end of the Dead Sea ; but along the line of the Jordanir Valley towards the Sea of Tiberias the displace- ment diminishes considerably, so that Crelaceou.s limestones are found forming both sides of the valley. The Jordan-Arabah 'fault' generally keeps very close to the base of the dill's forming the eastern margin of the vallej-, and numerous branching, or parallel, 'faults' accompany the main line of displacement, at least in the region south of the Dead Sea.
The floor of the Jordan-Arabah Valley is formed of alluvial terraces, gravel, blown sand, and mud flats. The terraces are of various ages, the more ancient occupying higher levels ; the more recent being only a little elevated above the waters of the Jordan and Dead Sea. The highest and most ancient of the terraces are those seen at Ayfln Buweirdeh, occupying a position in the centre of the valley about 30 miles S. of the southern end of the Dead Sea, and at a level nearly correspond- ing to that of the Mediterranean. They are formed of calcareous marls w'ith fresh- or brackish- water sheUs of the genera Neriliiia, Melanin, Melanopsis, etc., and point to a time when the waters of a great lake occupied a position about 1300 ft. above the present surface of the Dead Sea. This lake must have extended northwards, so as to include the whole of the Jordan Valley as far as the Lake of Hflleh, a distance of about 200 miles. Next in imi)ortance to the terrace above described is that which may be recognized all round the margin of the Dead Sea hollow, known as the ' Ghor,' rising about 600 ft. above its surface — and formed of saiiferous marls with gypsum on the west side, and of gravel and sand on the east. The salt terrace (Khasm Usdum) is referable to this horizon ; and besides this, there are two or three distinct terraces at lower levels. The sur- face of the Sea of Tiberias which lies in the upper part of the Jordan Valley is 6S2 ft. bclmv that of the Mediterranean, while the Lake of Ilflleh rises to 7 ft. above this level. Still proceeding north- wards the Jordan itself has its source in the copious fountains of Banias (Cafsarea Philippi) which burst forth, ' full grown at birth,' from liie base of Mount Hermon, fed by the well-nigh perennial snows which crown the dome - shaped summit, which, at a height of 10,(KX) ft. above the level of the .sea, dominates all objects terrestrial as far as the eve can reach.*
(4) The Tal/Uland of Edom, Moab, and the JaulAn. — "This section of country has to some extent been described under the head of the ArahaH (wh. see). Bounded on the west by the deep depression aliove described, it forms the western margin of the great Arabian Desert, the home of the wandering Budawin. Commencing on thenorlli at the baseof Mount Hermon, it stretches as a gradually ascending tableland southwards, through the Jauli'in and Ilaurfm (Trachonitis), into the ancient kingdoms of Amnion, Moali, and
* For an account o( Uicm ipring*, ••• TrisUmui, Land e) liratf, &isi.
152 GEOLOGY OF PALESTINE
GEOLOGY OF PALESTINE
Edom. Breaking off along a steep escarpment or Beries of scarps on the western side, on overlooking tlie Dead Sea it reaches a level of HOUO ft. ahove the Mediterranean, and fartlier south at Petra rises to still higher levels. In this latter part of its range the escarpment is much broken by ravines which penetrate its sides, and cause repetitions of the features along lines of 'faulting ; hut, on approaching the head of the Gulf of 'Akabah, the escarpment becomes more con.solidated, and the granite walls, [lenetrated by numerous igneous dykes of porpliyry, basalt, and diorite, rise with an abrupt ascent from the Valley of tlie Arabah to levels of 50UO or 6000 ft. above the surface of the gulf. Here the intensely red colour assumed by the rocks has given rise to the name Jcbel en-Nur (' mountain of tire') which is applied to the heights above 'Akabah. At this point the gorge of the Wady el-Ithem offers the only accessible road by which the Arabian Desert can be reached from the Arabah Valley until we arrive opposite Mount Hor (Jcbel H(iroun) at a distance of 45 miles to the northward, and this must conseq^uently have been the route by which the Israelites circumvented the land of Edom when marcliing towards the
iilains of Moab on their way to the Promised jand ; — the more direct way naving been denied them by the king of Edom (Nu 20"-=')- The flanks of the tableland are intersected by numerous channels of mountain torrents — those to the south- ward near 'Akabah being generally dry, except after thunderstorms, when they bring down quantities of stones and shingle which they throw out in fan-shaped ramps at the mouth of each wady. A perennial stream, however, flows throu<rh the Wady Mflsa at Petra and alon^ the Wady Haroun. But when we reach the borders of Moab and a region of greater rainfall to the northward, streams become more frequent and copious, and tlie Hessi, Kerat, the Arnon (Mojib), and Zerka Ma'in (Callirhoc), together with numerous smaller brooks, descend the slopes into the Dead Sea from perennial springs.