CHAPTER VIII.
REGION OF THE TÎH.
We had now entered the district of the Tîh plateau, as generally understood; but towards the south-eastern part of its extension its margin can scarcely be recognised. From the Wâdy el Ain northward and eastward, the country is formed of a succession of scarped ridges and valleys, with but little symmetry or order of succession; so that it is impossible in this district to say within many miles where “the escarpment of the Tîh” really begins or ends. This disarrangement of the geographical boundaries is, I need scarcely say, due to geological causes. The strata, instead of preserving a regular order of succession, according to which the limestone ridge forming the margin of the Tîh succeeds a plateau of sandstone, as in the district north of Debbet er Ramleh, are here broken into, and displaced, by several large “faults,” ranging both in northerly and easterly directions. Thus, the order of succession is disturbed, the strata are dislocated, sometimes repeated over again, and a series of scarps and valleys, transverse in direction to each other, are produced. Even when we had reached the limestone district new ridges of considerable elevation were descried far to the north and west, and it was a question whether these ought not to be taken as the boundary of “the Tîh.” As a geologist, however, I must hold that the Tîh begins with the limestone formation; though I doubt whether this ground of identification will be considered satisfactory by geographers. Another consequence of this irregularity in the contours is, that the southern drainage system is prolonged far inwards towards the north. Several of the faults, or lines of dislocation in the strata above referred to, were seen by us on our way, and as far as practicable laid down on the geological map which accompanies this volume.
Desert partridges appeared to be numerous in the Wâdy el Tîhyeh.[1] Shortly after entering we noticed several harriers soaring above the
- ↑ Probably “Hey’s Sand Partridge” (Ammoperdix Heyi).
