Page:Mount Seir, Sinai and Western Palestine.djvu/238

This page has been validated.
196
NARRATIVE OF AN EXPEDITION THROUGH ARABIA PETRÆA,

deep pink. The Cretaceous Limestone is coloured yellow, and represents the Chalk formation of Europe and the British Isles.

The Nummulitic Limestone is represented by a buff colour; but the boundary between the two limestone formations is intentionally indefinite, as it could only be determined with accuracy by a careful and detailed survey and examination of the whole region. Outlying patches of the Nummulitic Limestone occur in Palestine, and are taken from M. Lartet's map; but it is probable that the formation is much more largely represented than is shown on either of those maps. The two formations, although belonging the one to the Secondary, the other to the Tertiary, periods, are very closely connected in Palestine as far as the mineral characters are concerned, though the fossil contents are perhaps altogether different.[1] Both also contain beds and bands of flint or chert.

The Cretaceous Limestone underlies nearly the whole of the Jordan and Arabah Valleys, though concealed by more recent deposits, and is broken off along the line of the great Jordan Valley fault against older formations. This has been explained in a previous page (p. 76), and need not further be insisted on. But it is entirely owing to the presence of this leading line of fracture and displacement, and the subsequent denudation of strata, that this great valley exists, and that the eastern side is so mountainous and characterised by such grand features of hill and dale.

These limestones pass under a newer formation of calcareous sandstone in the direction of the Mediterranean. To this formation I have applied the name of "Calcareous Sandstone of Philistia," as it forms nearly the whole of that country, or at least is its foundation rock. It is probably of Upper Eocene age, and appears to be represented in Egypt by the sandstone formation ("Nicolien Sandstein" of Zittel) with fossil trees found overlying the nummulitic limestone of the Jebel Mokattam, near Cairo. It is coloured deep brown on the map.

The formations next in order approach more nearly those of our own time, and range from the Pliocene period downwards. They consist of raised beaches and sea-beds along the coast, and of lake beds in The Ghôr and Jordan Valley; they are coloured a light shade of green.

  1. Dr. Zittel states that although there is no definite line of division between the Cretaceous and Nummulitic formations of the Libyan Desert, the fossils of each formation are entirely different. It is probably the same in Arabia Petræa.