vegetation, amongst which the pretty ubiquitous plant (Zygophyllum)—beloved of the camel—with rose-pink or yellowish blossom, was conspicuous. This is "the erymth" of the Arabs, and is perhaps the most continuous of all the plants of the desert, as we met it at intervals all through from Ayun Mûsa to the vicinity of Jerusalem.
Fig. 4.—Sandstone Tor, resting on a basis of granite and porphyry. Seen from the Wâdy Berráh.
On descending into the W. Lebweh we were struck by the appearance,near the centre, of great tabular masses of very red granite (pegmatite) and porphyry, traversed by numerous basaltic dykes, ranging generally in north and south directions. These rocks weather dull brown; so that until I examined them closely and broke off fresh faces with my hammer, I mistook them for sandstone. In composition they consist of red felspar and quartz; and masses of this type predominate, as we found afterwards all through the mountainous part of the Sinaitic peninsula. These rocks are everywhere traversed by dykes of dark basalt, so conspicuous as to attract the notice of our dragoman, and even of the Arabs. One of these dykes can be traced by the eye for at least a distance of two miles; and towards the east it enters a basin in the mountains called "Bahera el Harriah."
On Saturday evening we camped in the Wâdy Lebweh, at the foot of a conical tor of granite, and at an elevation of about 3,800 feet. The air was cool and bracing. Before dinner I climbed to the top of the tor, and as the sun approached the horizon enjoyed an extensive prospect all around. To the north in the distance was the table-land of the Tîh, breaking off along
