Page:Mount Seir, Sinai and Western Palestine.djvu/217

Rh 3. A geological reconnaissance along the line of route through the districts of Sinai, Akabah, and the Wâdy el Arabah, including the following particulars:—

(a) Collections of fossils from the Wâdy Nasb Limestone; additions to those already made by Mr. Bauerman and Colonel Sir C. W. Wilson. These fossils (which are being examined by Professor Sollas) go to show that this limestone is of Carboniferous age. The Wâdy Nasb limestone was found to continue over a considerable region north of Mount Sinai, and was again recognised amongst the mountains of Moab on the east side of the Salt Sea in the Wâdy el Hessi. As this limestone rests upon a red sandstone foundation, this latter may also be assumed to be of the same geological age, and therefore cannot be the representative of the "Nubian Sandstone" of Rosiere, which (as Professor Zittel has shown) is of Cretaceous age. I propose to call this formation, therefore, "the Desert Sandstone." It forms, with the limestone, a strip along the borders of the ancient rocks of Paleozoic, or Archaean, age, and is about 400 feet in average thickness; the base is generally a conglomerate.

(b) Above the Wâdy Nasb limestone is another sandstone formation, of which a large portion of the Debbet er Ramleh is formed. It is laid open in the Wadies Zelegah, Biyar, &c., and along the mountains of Edom and Moab. Out of this rock have been hewn the ancient temples, tombs, and dwellings of Petra and the Wâdy Mûsa. It stretches along the southern escarpment of the Tlh plateau, and forms the base of the limestone cliffs along the margin of the Wâdy el Arabah as far north as Nagb es Salni. This sandstone formation is soft, red, or beautifully variegated. It is (in all probability) of Cretaceous age, and, if so, the true representative of the "Nubian Sandstone" of Eusseger. It will thus be seen that there are two red sandstone formations, one below, the other above the Carboniferous limestone of the Wâdy Nasb.

(c) The geological structure of the Wâdy el Arabah was examined throughout a distance of 120 miles from south to north. That it has been hollowed out along the line of a main fault (or line of fracture and displacement) ranging from the eastern shore of the Salt Sea to that of the Gulf of Akabah, was clearly determined. The position of the fault itself was made out and laid down on the map in six or seven places; one being about ten miles north of Akabah, another near the watershed,