Egypt Physical Structure and Soil Configuration

The territory of Egypt can be divided into four main types of landscape: the Etbāi mountains, the desert plateaus, the depressions of the oases, the Nile valley with its Delta. The former, formed by eruptive rocks and ancient crystalline schists, represent the N part of the crystalline base of East Africa, and constitute a bundle of short chains, which is the only mountain range in Egypt. This begins a little S. del W. el-‛Arabah and borders the Red Sea with a series of peaks: the main ones, the G. Ghārib (d. 1750), the G. ed-Dukhān (the Porphyrites mons of the Romans; m. 1670), G. esh-Shāyib which is the highest mountain in Egypt (m. 2184) and G. Ḥamatah (m. 1978). Further to the South. the beam expands and the watershed moves away from the sea; the highest peaks are el Gerf, 1258 m., and Korabkamsi, 1230 m., on the Eritrean side, and G. el-‛Iṣ (1736 m.) on the watershed. The region constitutes a maze of rugged, steep, sun-burnt reliefs: a stony desert of the most impervious, except in the valleys where shepherds find some underwater water and meager pastures. Towards the Red Sea, the range generally falls steeply on a narrow strip of coastline.

The desert plateaus are essentially made up of mainly calcareous and horizontal banks of the Tertiary and Cretaceous periods, and are crossed and separated in two parts by the Nile valley. On the right of this stretches, from Cairo to Qinā, the plateau known as el-M‛āzah, on average 300 to 400 meters high, covered with cerie and bare of vegetation, separated from the Etbāi by the longitudinal furrow of the W. Qinā. In the valley furrows, which affect its margin, a thin shrub vegetation is green. On the left of the Nile, the calcareous desert plateau forms an enormous triangle, of which one vertex corresponds roughly to Cairo, a second rests on the border, the third pushes towards the oasis of Sīwāh; the side between Wādī Ḥalfā and Sīwāh is made greatly jagged and irregular by the depressions of the great oases. The plateau partly has the character of ḥ am ā dah, or rugged and very arid stony desert; but there is no lack of important deposits of sand, sometimes very extensive, as in OSO. of el-Farāfrah and ed-Dākhlah, where they form an insurmountable obstacle to traffic. sometimes instead arranged in very long narrow chains, oriented according to the prevailing wind (N. or NW) such as that of Abü Muḥarrik, which extends to the North. of the oasis of el-Khārǵah, between it and Moghara for 670 km.

In the Libyan plateau the vast depressions in which the oases arise: the marginal ones (el-Khȧrǵah, ed-Dākhlah, el-Farāfrah) more or less open towards S., where the ground is formed by Nubian sandstones; the others (el-Baḥarīyah, Sīwah) completely or almost completely surrounded by limestone rock walls. The whole life of the Western Desert.

The Nile Valley (v. Nile) is a narrow strip of intensely cultivated and inhabited soil, the product of the alluvial deposits of the river, on whose banks it lies. After passing the first cataract in Aswan, the valley runs between two steep walls, sometimes more than 300 meters high at the bottom, which are then the fronts of the two side plateaus: the arable plain has an average width of 15 km. and extends especially on the right, while between it and the foot of the walls a pebbly or arenaceous band rises gently from a few hundred meters to 5 or 6 km., due to the rocky materials fallen from the walls and the conoids of the w ā d ī tributaries. At the height of Benī Suéf the valley widens and the side walls gradually lower, until starting from Cairo they diverge sharply and the plain expands like a fan, forming the Delta.

According to Thenailmythology, the Nile Delta measures 160 km. from S. to N. and 250 km. of maximum width: it is a vast alluvial plain, which descends very sweetly from 9 msm, at the S. end, up to the level of the sea. The plain is crossed by two branches of the Nile and by a complicated network of canals that plow in every direction a soil that is now finely arenaceous, now even clayey, but always substantial and deep (16-20 m.) And superimposed on a powerful mattress of gravel or yellow quartz sand quite rich in fresh water. Towards the north, the region is occupied for vast stretches by brackish lagoons, limited by narrow strips of littoral sand (see below: Hydrography).

The coasts of Egypt stretch along the Mediterranean for over 965 km. Rocky but weakly jagged and importuous in the Marmarica, that is between the Gulf of Sollum and the western edge of the Delta (in which section they run with a WW-ESE direction), they take on the character of a thin beach in correspondence with the broad convexity of this, interrupted only by the protrusions due to the mouth of the two Nilotic branches, which thus determine two large bays: that of Abukir (see abukir) west of the Rosetta estuary and another west of the Damietta estuary. Between the eastern edge of the Delta and Rafah, on the border of Palestine, the coast becomes naked and imposing again. The coasts of the Red Sea run from the NNW. to SSE. and are mountainous everywhere, fringed with breakers and coral reefs: the only two slightly notable protrusions are the Rās ez-Zeit towards the mouth of the Gulf of Suez, followed by a chain of islets, and Rās Banās near the place where the ancient city of Berenice stood.

Egypt Physical Structure and Soil Configuration