Occasional patches of blown sand are here met with, and the first well-marked dunes were crossed at 141 kilometres. From here onwards for kilometres the whole area was more or less sandy with occasional narrow well-marked ridges or dunes, running almost due north and south, and varying in breadth from that of a single line to a number of parallel ridges side by side half a kilometre broad. The largest dune of this group at 146½ kilometres is known as Ghard el Shubbab. The steepest sides are those facing west where the angle may reach 30°.
At the particular locality crossed by this road the sand area is very easily crossed, a circuitous route being followed in order to take advantage of the flatter dunes with the easiest slopes when crossing the steeper ridges. Probably the road crosses at one of the easiest points. This remarkable line of dunes, known as the Abu Moharik, has its origin in the neighbourhood of the oasis of Mogara and runs southward, almost without a break, across the desert until Kharga is reached, whence with a slight break owing to the broken character of the ground it continues southward within the oasis-depression. The total width of the sand-belt on the road under description is about 6 kilometres.
At 153 to 156 kilometres a number of black conical hills, Gar el Hamra, are situate from 1 to 2 kilometres from the road on the south side. One or two more sand-dunes were crossed and then the road, maintaining its direction of 2°-3° north of west, lay over a more or less uneven dark-coloured limestone desert broken up into a number of small hills. At 169 kilometres a broad ridge of sand-dunes was encountered, running 18° west of true north. These light yellow dunes afford a beautiful and remarkable sight, running northwards away to the horizon over a dark brown-coloured desert in an almost perfectly straight line and with a sharply maintained junction-line between the edge of the sand and the desert surface adjoining.
Within a few hundred metres of the western side of the sand-dunes the road commences the descent from the plateau into the oasis-depression. The road enters at the most northerly extremity of the oasis, the descent being particularly easy at this point, passing the large dark-coloured hill, Jebel Horabi (or Morabi?), on the right almost immediately afterwards.
A fine view of the depression is obtainable from the top of the escarpment, a broad low-lying expanse, bounded by steep escarpments or walls, stretching away to the south, its monotony relieved by several large flat-topped hill-masses, near which, on the lowest portions of the floor, dark areas, the cultivated lands and palm-groves can be distinguished. The road crosses the depression in a south-westerly direction, passes a spring known as Ain el Gidr, the first watering place, and divides in front of the great hill-masses separating the two groups of villages, the eastern branch keeping close under the eastern scarp of Jebel Mayesra, to avoid a large area of soft salty ground, and leading to the villages of Zubbo and Mandisha, While the western branch continues its course to the cultivation surrounding El Qasr and Bawitti. The distance by this road from Qasr el Lamlum Bey to the village of Zubbo is 190 kilometres and to Bawitti 195 kilometres.
Geology of the Feshn-BahariaHaving now described the topographical features of this road, the chief geological characters may be noticed. The plain between the Nile Valley cultivation and the scarp of the plateau is covered with sandy gravel, partly downwash from the higher ground in Recent times, and partly the remains of definite gravel deposits belonging to the Nile Valley Pleistocene series.[22] The pebbles now found strewn over the plain consist chiefly of flints, doubtless derived from the Eocene limestones forming the deserts on both sides of the Nile Valley, and occasional pebbles of hard felspar porphyry which must have originally been derived from the igneous massifs of the Red Sea Hills. Both are well rounded, although the former are frequently broken up into angular fragments by temperature changes. White granular beds of gypsum, of various degrees of impurity, crop out on the plain in places, and in all probability there was in Pleistocene times an extensive deposit of this mineral all over the surface of the low-lying country. In the desert lying between the Fayum and the Nile Valley further to the north, these gypseous beds occur of great thickness and wide extent, and the deposits crossed on this road are doubtless part of the same series.
The cliffs of Jebel Muailla to the north are capped by a hard dark bed of limestone, which weathers with a vertical face, while the more gentle slopes, generally more or less hidden with sand, are doubtless formed of softer limestones, marls, and clays. During the survey of the Fayum (see foot-note, [p. 17]) the hills surrounding Wadi Muailla were found to be formed of Lower Mokattam beds (Middle Eocene) and the hills seen from this road are doubtless composed of the same beds. The ridges crossed at 20 kilometres are formed of hard, compact, close-grained crystalline limestone, covered with more or less gypsum and flint gravel; the limestone beds forming these ridges show dips which suggest the existence of a fault running N.E.-S.W., parallel to the trend of the cliff behind, and this may be part of the extensive faults and folds of the Nile Valley. In one small hill (22 kilometres) shales with Ostrea were noticed at the base, with occasional hard oyster-limestone bands; the upper part was formed of 10 metres of gravel consisting of well-rounded limestone pebbles. This superficial deposit must be classed as Pleistocene and may be a sea-beach, though no conclusive evidence was obtainable on this point. The escarpment passed at 23 kilometres is capped by a bed of white limestone, shales forming the slope, but was not examined at close quarters. The floor of the bay formed by the receding cliff shows outcropping brown limestone with Ostrea, and the escarpment on the far side is capped by a hard white crystalline limestone with much flint, the latter forming bands. On the surface is a thin calcareous gypseous gravel deposit, doubtless of the same age as the gypseous beds already mentioned as occurring on the plain below. The flanks of the scarp are hidden by downwash. The cliff bounding this strip of plateau, 1½ kilometres further on, is composed of the same beds, the limestone being here silicified, with large silicified Conidæ. With regard to the age of these limestones and clays they are probably equivalent to part of the Lower Mokattam series already mentioned as forming the hill-masses round Wadi Rayan, although no Nummulites gizehensis beds were observed in the sections examined. A conspicuous black knob among the low gravelly hills left two kilometres on the right at 32 kilometres, was found to be a neck of hard dark andesitic basalt, one of the few occurrences of igneous rocks in the Western Desert. Several other similar looking dark hills were in sight, but time did not admit of their examination. The dark well-marked range 6-7 kilometres to the left of the road is probably identical with a range of hills occurring 10 kilometres west of Bahnessa, which was mapped[23] during the survey of the Nile Valley in 1899, and found to consist of a mass of andesitic basalt similar to that forming the small neck on this road. Doubtless they are both parts of the same intrusion. The surface of the plain is still composed in part of gypseous deposits, with occasional outcrops of the underlying limestone, the surface being covered with a certain amount of loose sand with rounded flints and their broken fragments. In the neighbourhood of Jebel el Ghudda the plain consists of limestone with numerous individuals of the large Nummulites gizehensis, and are thus of Lower Mokattam age. Much of the limestone is crystalline. The hills of Jebel el Ghudda are formed by younger overlying beds consisting of hard silicified sandstones and grits (quartzites), which lithologically are very similar to the beds of Jebel Ahmar near Cairo, of Oligocene age. They may, however, belong to the Upper Eocene series, so well developed above the Upper Mokattam in the escarpments to the north of the Fayum, as this series contains similar beds with similar silicified wood. They enclose bands of coarse conglomerate and have a peculiar blackish burnt colour. Occasional patches of these grits are here and there met with right up to the depression of El Bahr, and the silicified wood passed at 92 kilometres belongs to the same series of beds. From the scrub area at 93½ kilometres till the road approached El Bahr there was hardly a sign either of the grits or of section anywhere met with on this road. The depression is cut down through the upper series of sandstones and grits into the fossiliferous white limestones and sandstones below. The eastern scarp showed the following beds:—
| Top. | |||||
| Soft white Sandstone. | |||||
| Middle Eocene. | ⎧ ⎨ ⎩ | Limestone with Nummulitesgizehensis. | ⎫ ⎬ ⎭ | Lower Mokattam. | |
| Limestone with Ostrea, Exogyraand Lucina, etc. |
The floor is covered in places with numerous weathered out individuals of N. gizehensis and large oysters. Some of the hills occurring within the depression showed brown siliceous limestone overlying white limestones with beds containing Nummulites gizehensis, Ostrea, etc., below. In some of these hills the beds show evidences of folding, which like that within the Baharia Oasis may have partly caused the formation of the depression by bringing the softer beds to the surface within the reach of the agents of denudation. On ascending the western scarp, beds with Ostrea, Turritella, etc., were crossed, and near the top thick yellowish sandstones crowded with Ostrea occur. Two of the species of Ostrea were afterwards examined by Dr. Blanckenhorn, one of which he regarded as nearly related to O. Fraasi, and the other as a new species with affinities to O. Hess, May-Eym.
Probably the whole of these fossiliferous beds belong to the Middle Eocene Mokattam Series; the lower beds with N. gizehensis, are certainly Lower Mokattam, and probably the upper, although the latter may represent the base of the Upper Mokattam. Whether the upper bed of sandstone capping the eastern scarp belongs to the same series or is equivalent of the silicified grits with silicified wood passed further back is open to some doubt.