Page:Mount Seir, Sinai and Western Palestine.djvu/237

Rh gneissose, and schistose rocks, amongst which have been intruded great masses of red porphyry, dark greenstone, and other igneous rocks in the form of dykes, veins, and bosses. These rocks are probably amongst the oldest in the world, and are representative (at least in part) of those in Upper Egypt at Assouan (Syene) from which the noble monoliths of ancient Egyptian art have been hewn.

Two isolated masses of the granitic and sandstone formations occur amongst the limestones of the Tîh, and were discovered by Mr. Holland; but details regarding their relations to the newer strata are wanting.

After these ancient rocks had been consolidated they were subjected to a vast amount of erosion, and were worn into very uneven surfaces, over which the more recent formations were spread; first, filling up the hollows with the lower strata, and ultimately covering even the higher elevations as the process of deposition of strata went on.

The oldest of these formations is the red sandstone and conglomerate, which I have called the "Desert Sandstone" formation. It is coloured blue on the map, and forms a narrow strip along the margin of the old crystalline rocks. It is capped by the fossiliferous limestone of the Wâdy Nasb, which shows it to belong to the Carboniferous period—in fact, to be the representative of the Carboniferous Limestone of Europe and the British Isles. It is also found east of the Arabah Valley and amongst the mountains of Moab east of The Ghôr.

This is succeeded by another sandstone formation coloured yellowish brown, and more extensively distributed than the former. It belongs to a much more recent geological period, namely, the Cretaceous; and is the representative of the "Nubian Sandstone" of Roziere, so largely developed in Africa, especially in Nubia and Upper Egypt.

This is succeeded by the Cretaceous and Nummulitic Limestone formations, which occupy the greater portion of the map, forming the great tableland of the Tîh, from its western escarpment to the borders of the Arabah Valley, and stretching northward throughout the hill country of Judea and Samaria into Syria and the Lebanon.

On the east of the Jordan Valley the Cretaceous Limestone forms the tablelands of Edom and Moab; as far north as the Hauran and Jaulan where the limestone passes below great sheets of basaltic lava coloured