zizyphus were the most abundant, generally growing in picturesque clumps, with narrow glades between. The cultivated fields of the Ghawarueh spread around; and beyond, the river descending from the Wady el Hessi flowed between the plains and the mountain slopes, and bounded the cultivated lands towards the east. The grand mass of Jebel es Somrah, with its adjoining heights and deep ravines, formed the background at a distance of two or three miles; and from its ever varying colours, according to the position of the sun's rays and the time of day, formed an object of unwearied study to us during our long detention at Es Safieh. This mountain is remarkable for the interest attaching to its geological structure. Its base is formed of very ancient volcanic materials, consisting of successive beds of trap, porphyry, "ashes," and agglomerates—penetrated by numerous dykes, and dipping at a small inclination towards the north.
Upon this volcanic platform the horizontal courses of the Desert Sandstone formation repose, breaking off in great cliffs, and forming the flanks of the mountain to an elevation of about 3,000 feet above the base; finally, the sandstone itself is surmounted by an escarpment of limestone, which extends upwards into the table-land of Moab. It will be seen from the above description that this volcanic formation is of more ancient date than that of the Desert Sandstone, and consequently has no connection whatever with the present structure or formation of the valley.
Fig. 15. — Gorge of the W. el Hessi.
S Cliffs of red sandstone enclosing terraces of gravel, sand, and shingle (G) of the ancient Salt Sea (Bahr Lut), through which the valley of the River Hessi has been channelled out.
The southern flank of Jebel es Somrah terminates along the deep gorge called the Wady Salmoodh, the sides of which are in some places flanked by great beds of gravel rising to a level of 600 feet (by aneroid measurement) above the surface of the Salt Sea. These gravel beds may be
