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the Arabah Valley, what had been surmised by former observers, that the Jordan-Arabah depression is due primarily to a great fault, or fracture, of the strata, running generally along the base of the Moabite and Edomite hills, along which the strata have been displaced; those on the west having been relatively lowered with reference to those on the east, to the extent of 1,000 feet and upwards.* On this account it is that the Nubian sandstone formation appears along the eastern side of the Ghor, but never on the western, that side being formed of Cretaceous limestone; while, in the southern part of the Arabah Valley, the eastern side is formed of still more ancient crystalline rocks. The elevation of the low saddle or watershed which crosses the Arabah Valley from side to side was also determined to be about 700 feet at a distance of forty-five miles from the head of the Gulf of Akabah; and I came to the same conclusion as Professor Lartet, that the waters of the Jordan never flowed into that gulf, but that, on the contrary, ever since the land emerged from the ocean, there had been a continuous ridge separating the waters on either hand.†

I have endeavoured in the Geological Memoir to trace the succession of operations and events by which the JordanArabah Valley has been formed, and must content myself here with stating that, as the whole region was under the bed of the sea down to the close of the Eocene period, the elevation of the land, together with the development of the main physical features, may be referred to the succeeding Miocene-a period remarkable for physical disturbances and great denudation of the strata over the Europasian continent, and the adjoining parts of Africa.

(4.) The formation of the table-land east of the JordanArabah depression was a necessary result of the physical operations by which this depression itself was formed. The strata which were lowered on the west, were elevated on the east, side of the great fault, and have been converted into a high table-land with an average level of 5,000 feet

* This view has been advanced by Tristram, Land of Israel, and Lartet, Géologie de la Mer Morte, but the actual line of fracture had not previously been traced along the Wady el Arabah.

+ In a recent review of the Geological Memoir in the Saturday Review, April 17, the writer advocates the view that a river originally poured its waters into the sea on the site of the present Gulf of Akabah, and that the depressions and ridges crossing the valley are due to movements of the crust which took place subsequently to the north and south faulting. This view has been deliberately rejected by both Dr. Lartet and myself, for reasons which I have fully explained in the July number of the Quarterly Statement P. E. F.

above the sea in the Edomite district, or 4,000 feet in that of Moab. The upper surface of this table-land is formed, throughout the greater extent, of Cretaceous limestone resting on Nubian sandstone, and this again on ancient crystalline rocks which form the basis of the whole region, and emerge from beneath the Nubian sandstone on approaching the head of the Gulf of Akabah from the north. The ancient city of Petra, whose temples, palaces, theatres, and tombs are hewn out of the solid sandstone rock, in situ, lies in the heart of the mountains of Edom, and was visited by the members of the Expedition. The summit of Mount Hor (Jebel Haroun) was also reached, and its elevation of 4,580 feet above the sea determined. This point, which commands a view of the Ghor, the hills of southern Palestine, and those of the Peninsula of Sinai, was made by Colonel Kitchener a principal trigonometrical station.

The Valley of the Arabah has been for ages the line of communication between Syria, Palestine, and the great Arabian Peninsula. Along this valley the Israelites, on being refused a passage through the territory of the King of Edom, retraced their steps from Kadesh Barnea and Mount Hor, and crossing the mountain range by the pass of the Wâdy el Ithm skirted Mount Seir on their progress northwards to the tableland of Moab. Along this line of march also, at a later period, the Queen of Sheba may be supposed to have journeyed from her territory at the head of the Persian Gulf, when she visited King Solomon, and, having crossed the Desert of Arabia, took the line of the valley from Elath northwards to Jerusalem. By the same line Solomon kept up his communication with the port of Ezion Geber,* which Leon de Laborde has, with every probability, identified with the Island of Jazirat Farûn-off the Ras el Musry-at the western side of the Gulf, opposite Akabah. The only existing remains on this island are considered to belong to the period of the Crusades.

(5.) The fifth and last physical district, the Peninsula of Sinai, is by far the most striking, from the grandeur and loftiness of its mountains, their sharpness of outline, and the depth of the colouration of the rocks, in which red and purple colours prevail. It thus presents a marked contrast to the table-land of Badiet-et-Tîh, and of Southern Palestine to the north, where the nearly horizontal beds of limestone give rise to terraces, with prevalent grey or yellow colours, except where clothed with herbage. The physical features of this region

VOL. XXI.

* 1 Kings ix. 26.

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have been so fully described, especially by the late Professor Palmer, Sir Charles Wilson, Oscar Fraas, De la Borde, Dean Stanley, and others, that little need be added here. From the summit of Mount Sinai Colonel Kitchener was able to take the bearings of numerous points with the theodolite, and thus to connect the triangulation of the Peninsula with that of Southern Palestine along the Arabah Valley. The magnificent survey of the Sinaitic Peninsula by the officers of the Ordnance Survey had left little to be desired. Where it terminated towards the Gulf of Akabah it was taken up by the members of our Expedition, and the result is an elaborate map of the Valley of the Arabah, from the head of the Gulf of Akabah to the shores of the Dead Sea. And in a reduced copy of this map (on a scale of six inches to the English mile) I have inserted the geological details with as much accuracy as our reconnaissance would permit.*

The rocks of the Sinaitic mountains, including Jebel Serbal, are formed chiefly of granite, gneiss, various schists, invaded by porphyry and other igneous rocks. It is probable that these represent the oldest formation of the globe, known to geologists as "Archæan." Traced westward beyond the shores of the Gulf of Suez, they form much of the mountainous tract between the Red Sea and the Valley of the Nile, where they reappear, rising from beneath the Nubian sandstone at Assouan.

In the Sinaitic Peninsula the crystalline rocks are overlain in certain directions by Carboniferous beds, originally discovered by Mr. Bauerman in the Wâdy Nasb, and visited by the members of the Expedition. These consist of red sandstone and conglomerate, overlain by limestone with numerous shells, crinoids, and corals, identical with, or allied to, those of the Carboniferous beds of Europe and the British Isles. Numerous specimens of these fossils were collected and brought home for determination, and have served to place beyond doubt the geological age of the strata in which they occur.+

Throughout the Sinaitic Peninsula, evidences of the former existence of lakes and chains of lakes were not infrequent in the occurrence of deposits of marl, beds of gravel and sand forming horizontal strata over some of the plains and valleys. It was also clear that at a former period the now waterless valleys had been occupied by large, and probably

* The preparation of this map was undertaken by Mr. Armstrong (formerly Sergeant-Major, R.E.), of the Ordnance Survey of Palestine. †The determinations were made by Prof. Sollas, of Dublin University, and are given in the Memoir, p. 48.

perennial, streams, as old river terraces were found rising several feet above the present beds of the valleys. The presence of such terraces is not to be altogether accounted for from the occurrence of occasional thunderstorms (or "seils" of the Arabs), which in winter burst upon the mountains, and send down great torrents of water. In traversing the remarkable gorge of the Wâdy el Ain, we had occasion to observe the effects of such floods in piling up boulders, shingle, and drift-wood at the headings of the valley.

Recent changes in the climate of Arabia Petræea and Palestine. -This brings me to the last point which it is necessary to refer to in this communication, namely, the evidence of a former climate more closely resembling that of central Europe and the British isles. Although part of this region is generally regarded as rainless, this is not exactly the case, as a little rain, generally accompanying thunderstorms, falls in the winter time, and the summits of the Sinaitic mountains, according to Sir Charles Wilson, have a capping of snow for a short period, from which the perennial springs are fed. But the climatic conditions must have been very different from the present only as far back as the Glacial epoch, when glaciers descended the valleys of Lebanon to a level of 4,000 feet above the sea. As Šir J. D. Hooker has shown, the grove of

the venerable cedars decorates the surface of an ancient moraine which was thrown across the valley, and was formed at the end of a glacier which descended from the snowfields above. It may be supposed that at this epoch the annual mean temperature of Palestine and Syria was 25° Fahr. lower than at present, and that the rainfall was very considerably in excess of the present amount.

The melting of the snows on the Lebanon, and the large amount of rainfall may be considered as a sufficient reason for the high level at which the waters of the Jordan-Valley lake formerly stood, and for the size and depth of many of the old river valleys, such as those of the Zelegah and El Ain, in the Sinaitic Peninsula. I have also ventured to suggest the probability that during this epoch the volcanic fires of the Jaulan and Hauran were still in activity, the waters of the great lake, finding access through the faults and fissures of the Jordan Valley, having supplied the steam-power (so to speak) now generally recognised as a necessary agent in volcanic explosions. If this be correct, then we may further assume that with the drying up of the waters and their recession into their comparatively narrow bounds, such as they now occupy, the volcanic action concomitantly subsided, and ultimately

died out. Thus there may be said to have been a secondary connexion between meteoric and volcanic phenomena.

The effects of the humid climate must have remained for a long time after the humidity itself had diminished. These effects. would appear in the luxuriousness of the vegetation, and in the presence of extensive forests, of which hints are afforded in passages in the Old Testament and in other writings.* The cutting down of the forests and neglect of planting have probably greatly contributed to the present dryness of the climate; while the soil has been washed down from off the hill-sides, which present a remarkably bare and rocky aspect over a large part of Central Palestine and Arabia Petræa. Planting and irrigation would undoubtedly go far to restore to Palestine its former character for fruitfulness.

The natural flora of Palestine and its borders is known to be remarkably varied; and, in consequence of its peculiar physical features, the elevation of its hills and table-lands, and the depth of its valleys,-this country seems adapted for almost every kind of vegetable product. Tropical plants find a genial habitat in the Jordan Valley, while the hillsides offer a fitting climate for sub-tropical and temperate forms, and for the planting of forests. In Southern Judæa, thousands of acres of rich soil, adapted for the growth of wheat and other cereals, lie uncultivated and afford only pasture for the small flocks of sheep and goats of the Bedawin. When riding over these great expanses of pasture-land, once thickly populated, now almost without inhabitant, I often thought, What more favourable home for industrious colonists could be found in any part of the world?

[Professor HULL added that he had been asked whether the geology of the district affords grounds for believing that the river Jordan discharged its waters into the Gulf of Akabah prior to the formation of the depression alluded to in the address. He desired to say that the question was one on which he had a very strong opinion, and one which he had had to defend recently against a writer in the Saturday Review. He believed that from the time that region was elevated out of the sea the waters of the Jordan never flowed into the Gulf of Akabah. There was at the beginning, in his opinion, a lake which had its limits towards the south in the region of the Arabah Valley and the waters never flowed further, there being always an excess of evaporation beyond supply in that district.]

*Theophrastus, De Hist. Plant., lib. ii. cap. 81; Pausanias, lib. ix. c. 19; Horatius, Epist. 1. ii.; Pliny, lib. xxiii. c. 4, &c.