Looking westward through the inverted arch formed by the two hill-staples of the Khuraytah, and down the long valley which had given us passage, the eye distinguishes a dozen distances whose several planes are marked by all the shades of colour that the most varied vegetation can show. There are black-browns, chocolate-browns, and light umber-browns; bright-reds and dull-reds; grass-greens and cypress-greens; neutral tints and French greys contrasting with the rosy pinks, the azures, the purples, and the golden yellows with which distance paints the horizon. From a few feet above the Col-floor appear the eastern faces of the giants of the coast-range; and our altitude, some 3800 feet, gave us to a certain extent a measure of their grand proportions. We now stand upon the westernmost edge of the great central Arabian plateau, known as El-Nejd ("the Highlands"), opposed to El-Tihámah, the lowland regions. In Africa we should call it the "true" subtending the "false" coast; delightful Dahome compared with leprous Lagos. This upland, running parallel with the "Lip"-range and with the maritime Gháts, is the far-famed Hismá. It probably represents a remnant of the old terrace which, like the Secondary gypseous formation, has been torn to pieces by the volcanic region to the east, and by the plutonic upheavals to the west. The length may be 170 miles; the northern limit is either close to or a little south of Fort Ma'án; and we shall see its southern terminus sharply defined on a parallel with the central Shárr, not including "El-Jaww."[EN#155] An inaccessible fortress to the south, it is approached on the south-west by difficult passes, easily defended against man and beast. Further north, however, the Wadys ‘Afál near El-Sharaf, El-Hakl (Hagul), and El-Yitm at El-‘Akabah, are easy lines without Wa'r ("stony ground") or Nakb ("ravines"). The Hismá material is a loose modern sandstone, showing every hue between blood-red, rose pink, and dead, dull white: again and again fragments had been pointed out to us near the coast, in ruined buildings and in the remains of handmills and rub-stones. Possibly the true coal-measures may underlie it, especially if the rocks east of Petra be, as some travellers state, a region of the Old, not the New Red. According to my informants, the Hismá has no hills of quartz, a rock which appears everywhere except here; nor should I expect the region to be metalliferous.