Coming to Petra from Eljy, on the east, the body of the regular mountain on that side is limestone, and higher than the red sandstone, where the tombs in Wadi Mousa are excavated. The cliffs at Petra are of red sandstone, which is soft and easily cut, causing the sculptures to decay quickly, unless where they may have been protected from the weather. This formation extends far to the north and south, and rests on the lower masses of porphyry.
The colour of the sandstone rocks in Wadi Mousa is not a dull monotonous red, but a variety of bright hues, “from the deepest crimson,” as Dr Robinson writes (vol. ii., p. 531), “to the softest pink; verging also sometimes to orange and yellow. These varying shades are often distinctly marked by waving lines, imparting to the surface of the rock a succession of brilliant and changing tints, like the hues of watered silk, and adding greatly to the imposing effect of the sculptured monuments.”
The site of Petra, in the high ravine, is called by the Arabs, Wadi Mousa; most likely corrupted from Moseroth, or Mosera (Deut. x. 6), “where Aaron died and was buried.” It is extremely interesting, and is well watered by a flowing stream—the El Syk of Burckhardt. The sandstone rocks, with their craggy and precipitous sides, have their summits resembling rounded peaks; peaks, probably owing to the softness of the stone, rounded by the effects of weather. The height of this Wadi is estimated at near 2200 feet above the adjoining Wadi-el-Araba. To the west of Petra, Mount Hor, Gebel Harun constitutes the loftiest point of this sandstone tract. It stands out conspicuously, and is a cone irregularly truncated with three rugged peaks, of which that to the NE. is the highest, and has upon it the Mahommetan Wely; or the tomb of Aaron, called Neby Harun. This peak rises to about 2700 feet above Wadi Mousa, or to 5300 feet above the sea.
Captains Irby and Mangles, the first Europeans who ascended Gebel Harun, thus describe “the view from the summit.” It “is extremely extensive in every direction; but the eye rests on few objects which it can clearly distinguish, and give a name to, although an excellent idea is obtained of the general face and features of the country. The chain of Idumean mountains, which form the western shore of the Dead Sea, seem to run on to the south, though losing considerably in their height. They appear in this point of view, barren and desolate. Below them is spread out a white sandy plain, seamed with the beds of occasional torrents, and presenting much the same features as the most desert parts of the Ghor. Where this desert expanse approaches the foot of Mount Hor, there arise out of it, like islands, several lower peaks and ridges, of a purple colour, probably composed of the same kind of sandstone as that of Mount Hor itself, which, variegated as it is in its hues, presents in the distance one uniform mass of dark purple. Towards the Egyptian side there is an expanse of country without features or limit, and lost in the distance. The lofty district which we had quitted in our descent to Wadi Mousa, shuts up the prospect on the south-east side; but there is no part of the landscape which the eye wanders over with more curiosity and delight than the crags of Mount Hor itself, which stand up on every side, in the most rugged and fantastic forms, sometimes strangely piled one on the other, and sometimes as strangely yawning in clefts of a frightful depth.”
Under the term Nabathæan Chain, or the chain of the mountains of Edom, I have restricted those mountains beginning north of 30° N. Lat., and which then tend round northward, by the east of Petra. They are the loftiest on the east, attaining probably to an altitude of 3000 feet above the Wadi-el-Araba. This chain presents to the view, on the east, long elevated ranges of limestone, sometimes with flints, but of more easy slopes, without precipices, being smooth and rounded. Further still to the east, the high plateau of the Great Eastern Desert—of which El Nejd is a portion—stretches out to an almost indefinite extent. To the west and north, and around Mount Hor, lofty party-coloured sandstone ridges and cliffs prevail; then succeed high masses of porphyry, constituting the body of the mountains, but lower than the sandstone. And, lastly, more northwards, the chain sinks down into low hills of argillaceous rock, or of limestone.
The entire breadth of the Seir range seems not to exceed eighteen English miles, between Wadi-el-Araba and the Eastern Desert; whilst that of the more northern, or Nabathæan chain, does not exceed twenty-two miles between those districts.
Going west from Petra, the valley of the Araba is again entered, where the deeper Wadi-el-Jeib is seen to wind along, very near the middle of it, from the south, then sweeping off NW., it meets the Wadi-el-Jerafah, which comes in from the SW. Afterwards, it is called only Wadi-el-Jeib; and being a deep valley within a larger valley, it forms the chief water-course of the greater portion of the Araba, and carries down to the Dead Sea, in the wet season, an immense body of water.
El Araba, more to the north of Gebel Harun, is much wider; in parts of it there are gravel hills; and here and there, masses of porphyry lie about in the sand, having been washed down by the torrents. Eleven or twelve miles north of that Mount (Hor), occurs the pass of Nemela among low hills of limestone, or rather a yellowish argillaceous rock, the dark steep mass of the mountain being porphyry, as before described; thence the Wadi ascends between the porphyry and limestone formations; and on the top is a little basin of yellow sandstone capping the porphyry.
Coming back southward through the Wadi-el-Araba, as far as the embouchure of the valley of the Jerafah—meaning “gullying,”—which is about a mile wide, the mountains on this west side are found to be composed of chalk and limestone; and, in many places, with large pieces of black flint.
On the north, and to the east of Lussan, the mountains of Idumæa are lofty, consisting of precipitous limestone ranges; the solitary conical mount, about 600 feet above the plain, named Gebel Araif-el-Naka—“the crest of a she-camel,” forms a conspicuous object; it is calcareous, and strewed with flints. Low ridges extend from it westward and eastward; the latter terminating in a headland or bluff, called Gebel Makrah.