Page:Mount Seir, Sinai and Western Palestine.djvu/104

76 may be inferred, due to similarity in the physical conditions. Throughout the whole extent of the tract described, the strata of the earth's crust have been fractured and vertically displaced, so that those on the eastern side of the fracture have been relatively elevated, or (in other words) those on the western relatively lowered. This fracture is known amongst geologists as a “fault,” and in consequence of the displacement above stated, the rocks and formations on opposite sides of this depression do not in general correspond to each other.

The existence of this great line of fracture along the depression of the Jordan Valley and of the Arabah has been recognised by Hitchcock, Tristram, Wilson, and Lartet, who has in the clearest manner demonstrated the physical results of the displacement in the region of the Salt Sea and Jordan Valley. These observations I have had an opportunity of continuing throughout the whole length of the Wâdy el Arabah, and I have succeeded in tracing the line of this fracture from The Ghôr to the Gulf of Akabah, throughout a distance of about 120 miles. The details of the geological structure of this tract will be published elsewhere; but I may here state that the line of fault generally runs along the eastern side of the valley, and close to the base of the mountains of granite and porphyry, where its position has been determined at frequent intervals by the broken and disconnected stratification. The general direction of the fault is N. 10° E. A general section across the centre of the valley from west to east, such as that given in the adjoining page (Fig. 7), will serve to explain the relations of the formations on either side, and show the effects of the break and displacement in producing the striking contrast in the position of the formations, and in the character of the scenery, on opposite sides of the valley.

From this section it will be seen that the limestone (L) of the table-land of the Tîh, which comes down to the valley and forms its floor underneath the superficial gravel, is broken off against the granite and porphyry (G.P.) of the opposite side; while the limestone itself is lifted vertically into