CHAPTER III.. * * * * *

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THE ROADS CONNECTING THE OASIS OF BAHARIA WITH THE NILE VALLEY AND OTHER OASES.

The roads traversed by the Survey parties between Baharia and other places are three in number, viz., from near Maghagha and from Minia in the Nile Valley, and from Baharia to Farafra Oasis. Other well-known routes run from the Fayum, from Bahnessa, Samalut (Ascherson) and Delga, in the Nile Valley, from Alexandria, via Mogara, and from Siwa (Jordan, Cailliaud). The Survey’s return traverse to Minia from the south end of Baharia did not follow any defined road, but kept on the open plateau on a course computed from the known positions of the points of departure and destination.

The road from Feshn and Maghagha to Baharia leaves the edge of the Nile Valley cultivation at Qasr el Lamlum Bey, which bears 51½° west of true north from Maghagha railway station, and is distant 15·4 kilometres. From this point the road is well-defined and easily followed right into the oasis. In the following description the distances are given from the edge of the Nile Valley cultivation.

The road at first leads over a strip of drift sand, half a kilometre broad, with short prickly scrub, passing a white mosque on the left and then turning off somewhat to a direction 26° south of west, and continuing in a straight line for 15 kilometres over an undulating gravelly plain. The high prominent cliffs, about 7 or 8 kilometres to the north-west, are the flanks of Jebel Muailla, and a valley known as Wadi Muailla leads through them to the Wadi Rayan in the Fayum depression. At 19 kilometres the valley scarp, with a number of isolated peaks, is approached on the right, while ridges and low mounds form the plain below, well-marked lines of drainage running from here in a south-east direction towards the cultivation. At 23 kilometres the scarp runs back, enclosing a large bay, across which the road runs and ascends to the plateau beyond at 27·8 kilometres. Numerous isolated parallel sand-dunes in the form of small ridges are seen running out into the bay from the cliff at the far end, all lying slightly west of north and east of south, or parallel to the normal wind direction.

The escarpment bounding the Nile Valley at this point is only some 15 metres in height, being thus quite insignificant compared with the cliffs on the east side. The plateau here was found to be about 140 metres above the cultivation, the road having risen gradually throughout. The latter continues for about 1½ kilometres across the strip of plateau when it again descends, making a slight detour to the left for easy descent. It then continues 9° south of west, slightly winding, over gravelly undulating ground. At 31-32 kilometres a line of low hills is passed on the right, while a dark well-marked range lies 6-7 kilometres to the left.

A ridge of sandstone, known as Jebel el Ghudda, is passed on the right at 45 kilometres, from the end of which a small dune runs out; beyond, the plain resumes its monotonous undulating character, a low ridge being crossed at 61 kilometres. There, the road, consisting of a number of more or less parallel well-marked narrow paths worn by camels, which have a somewhat general habit of marching in line one behind the other, changes its direction to 36° south of west, falling gradually in level until a patch of scrub is reached 6½ kilometres further on. This scrub was dead at the time of the visit, and furnished a useful supply of fuel. From this point the course is 7° south of west (true), which direction is maintained for the next 42 kilometres over a remarkably monotonous undulating gravel-covered desert, the typical “serir” of the Arabs. At 92 and 93½ kilometres some more patches of dead scrub were passed on the right, while logs of silicified wood were noticed strewing the plain on the left. An Arab grave was met with at 96 kilometres, while skeletons of camels lie about near the roadside at frequent intervals; at 110 kilometres the eye of the traveller is relieved by a small grove of green thorny flat-topped acacia trees (Acacia nilotica, or “sunt” of the Arabs) with a patch of coarse grass; four gazelle (probably Gazella dorcas) were observed browsing on the scrub here.

The course now continues 12½° south of west, over gently undulating gravelly “serir”, until the eastern scarp of El Bahr is reached at 125 kilometres from the cultivation of the Nile Valley. The “serir” or undulating gravelly type of desert then ceases.

El Bahr is a depression, some 60-70 metres deep, cut out in white limestone rocks; its breadth at the point crossed by the road was 8 kilometres. Within it are several high prominent hills, one of which near the centre on the left side of the road is called Jebel Gar Marzak. The bottom of the depression was quite green with vegetation; sufficient water is said to fall every year to keep these plants alive, and in 1894 rain is said to have fallen to such an extent that a pool of considerable size was formed; the silt deposited by this is plainly visible at the present time. A good deal of blown sand occurs within the depression. El Bahr evidently corresponds to the Bahr Bela Ma, (river without water) figured on some authors’ maps, which has been frequently but erroneously referred to as an old river-course; although this idea was shown to be untenable by Zittel and Ascherson it has subsequently been maintained by non-scientific writers. No traces of any river deposit occur in the depression, which consists simply of a series of unconnected depressions, eroded by wind-borne sand.

The track leaves the depression at 134 kilometres, rising over heavy sand; it then continues 3° north of west. The character of the desert has now completely changed, and instead of the smooth undulating gravelly “serir,” its surface is rough and hummocky, being formed of hard bare limestone, cut up into sharp knobs and grooved into furrows by the powerful action of wind-borne sand; it resembles closely the surface of the rough open sea. This type of desert is spoken of as “kharafish” by the Arabs. While the “serir” forms an ideal surface for travelling over, the “kharafish” is the worst imaginable, the innumerable hillocks necessitating incessant small deviations, while the hard rough surface is in some places very troublesome to camels; moreover, an extensive view is out of the question and no tracks are visible on the surface, so that the road is easily lost except where marked by frequent cairns built of loose stones.

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.

Having 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. 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 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:—

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Soft white Sandstone.

{ Limestone with Nummulites gizehensis. } MIDDLE { } Lower EOCENE. { Limestone with Ostrea, Exogyra and } Mokattam. { 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.

Beyond the Bahr the desert is formed of a hard limestone much cut up by the action of wind-borne sand as already mentioned. This limestone is very unfossiliferous, occasional obscure nummulites seen on fractured or smooth surfaces being the only indications of its Eocene age.

The conical-peaked hills of Gar el Hamra on the left of the road at 151 kilometres were so striking that a detour was made specially to examine them. They were found to be composed of black ferruginous silicified sandstone or quartzite at top, with false-bedded sandstones below. They overlie nummulitic limestones forming the surrounding plain, and are not improbable Post Eocene lacustrine deposits, similar to those within Baharia Oasis (see pp. 60-62).

From here onwards up to the oasis-depression the plateau consists of hard brown limestone, more or less silicified, and contains nummulites and oysters. The Eocene strata, thus extend right up to the escarpment of the depression on the north side of the oasis. The geological structure within the depression will be found discussed in Chapter V.

Road from Minia to Baharia.—The cultivated land extends for some 9 or 10 kilometres west of Minia town, and at the time of the Survey expedition (early in October, 1897) this area was mostly covered by flood-water. Boats were therefore taken to the edge of the desert, and the march west was commenced from Nasl Nadiub Lengat, a small village on the cultivation-limit in lat. 28° 6′ 24″, long. 30° 39′ 45″ E., bearing from Minia railway station 9° north of west, distance very nearly 10 kilometres. The road westward being ill-defined, and the party knowing that any course followed a little north of west would surely lead to the oasis, no attempt was made to follow the track precisely, the course being rather chosen to take advantage of commanding points so as to map as much topography as possible en route. As will be seen further on, however, the road was struck some distance before reaching the oasis, and was thence followed to Zubbo.

On leaving Nasl Nadiub Lengat the course first taken was about 32° north of west. The desert here rises very gradually from the flood-level, (i.e. about 40 metres above sea-level), there being no cliff bounding the Nile Valley on the West at this point. For about 6 kilometres the ground was sandy, with occasional patches of flood-water and some grass; then came a stretch of level gravelly ground, and at 11½ kilometres some low sand-dunes were crossed. The course was now changed to about 3° south of west, and at 14 kilometres a descent was made from the gravel-plain into a limestone-depression, with gravel-capped eminences on either side. At 22 kilometres the gravel-strewn plain was again come on, a few low mounds, also gravelly, being passed at 31 kilometres, and camel-tracks, doubtless part of the Minia-Baharia road, being noticed coincident with the survey line at 37 kilometres. Continuing following these tracks, another camel-road was found to branch off at 46 kilometres to the north-west. The march was continued along the same track going a little more south of west, over a monotonous gravelly plain, with limestone showing through it in small patches, till at 78 kilometres from Nasl Nadiub Lengat a conspicuous though small mass of fissile gritty limestone was come on, which afforded a good survey-station. North and west of this are low gravel-covered hills. Turning a little north of west, a large extent of low table-like hills was seen on the south. At about 90 kilometres low plateaux of limestone, capped by gravel, closed in so as to form a defile about a kilometre wide, through which the line of survey passed, and at 98 kilometres a large sandy and gravelly depression, bounded by limestone scarps and containing numerous large limestone hills, was entered. Within the depression the course followed was about 30° north of west, so as to map roughly the escarpments on either hand. About 10 kilometres from the point where the depression is entered a long stretch of heavy sand was crossed beyond which tracks going west were come on, and the edge of the limestone plateau on the left curved round so as to cross the road. Ascending this low scarp at 116 kilometres, the course lay over white limestone, with sharp angular flints on its surface, and low limestone hills on either side. At 124 kilometres the broad belt of sand-dunes, the Abu Moharik, was reached. The dunes, which are of considerable height, run nearly north and south, and have a total width of some 4 kilometres; they formed the most serious obstacle of the entire journey. Beyond the dunes is a hard limestone plain, crossed by a low ridge (forming part of a higher plateau) at 136 kilometres. Beyond this ridge are low limestone-hills on either side, the floor being generally of hard white limestone. At 151 kilometres an oval depression in the limestone plateau, with its longer axis (about 4 kilometres) running W.N.W., was entered; this depression is full of hills of white chalk, which also forms the floor here. Ascending the opposite scarp of the depression at 159 kilometres, a narrow strip of higher plateau of much harder limestone was crossed, the edge of the scarp of the oasis of Baharia being reached at 160 kilometres, after marching for 57 hours from Nasl Nadiub Lengat. Up to this point there had been a gradual rise of the ground, from 40 metres at the Nile Valley to 265 metres above sea-level at the edge of the oasis.

The descent into the oasis is not difficult, the scarp being sandy and the fall gradual. At about 4 kilometres W.N.W. from the edge of the scarp is the first well or spring of the oasis, Ain Gelid (lat. 28° 19′ 28″ N., long. 29° 8′ 40″ E. of Greenwich), a small pool surrounded by grasses and with a tree growing near it. The barometric observations gave for this point the level 134 metres above sea, so that the total drop from the edge of the scarp is about 130 metres. From Ain Gelid the village of Zubbo bears about 15° north of west, and is some 17 kilometres distant, but owing to the hills between the two places necessitating a slight detour, the actual distance to be traversed is a few kilometres greater.

The road from Minia to Baharia shows essentially the same geological features as the one from Maghagha already described. The gravel which strews so large a portion of the road to the east is mainly composed of quartzite and flint pebbles, of a prevailing brown colour. Some of the rounded flints show a concentric structure, and are evidently segregation-nodules derived from chalk-beds; a very fine specimen of these, measuring some 20 c.m. in diameter, of almost perfectly spheroidal form, was obtained. The gravelly covering is frequently very thin, the limestones underlying it showing through in numerous places. No evidences of the precise age of this gravel have come to the authors’ knowledge, but it is certainly Post-Eocene. It appears to be the same formation which is found covering the edge of the plateau west of Girga and south of Assuan (east bank) and at various other points of the Nile Valley. It overlies beds of every age from the Nubian Sandstone to the Lower Mokattam.

The limestones which underlie the gravel near the Nile, and which are well exposed in the depression crossed 14 kilometres from the edge of the cultivation, are crowded with nummulites of various species, N. gizehensis and N. curvispira being specially common; these rocks belong therefore to the Lower Mokattam Series (Middle Eocene).

The limestone underlying the gravel further west (from about 30 to 80 kilometres west of the cultivation-limit) is only seen in small patches; it varies in character, being in some places loose and tufaceous in texture, and in others gritty and fissile, passing into a calcareous grit. The mass of gritty limestone at 78 kilometres, noted above, is about 6 metres in length by 2 metres high and broad; it shows a peculiar stalagmitic structure, the layers always parallel to the free surface. Several smaller masses found around all show a similar structure, and where the rock is exposed on the floor concentric fissuring is frequently seen. The sand which strews the surface here is largely calcareous, being doubtless in part derived from the gritty limestones.

The eastern part of the low hills lying to the left of the track at about 85 kilometres from the cultivation-limit show the following section (total height about 13 metres):—

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1. Flinty gravel, the flints containing nummulites.

2. Tufaceous white limestone.

3. Hard pink siliceous limestone.

4. Fissile sandy marls and gritty limestones.

On the western part of the hills the gravel covering is absent, the succession here seen being:—

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1. Sandy marls, 60 centimetres.

2. Very hard pink calcareous grit, 1 metre.

3. White sandy marl, fissile, 2 metres.

4. Soft red and white marls, 10 metres.

No fossils were seen in these beds except the nummulites in the gravel, which prove the latter to be at least in part derived from Eocene deposits.

The hills left of the road a little further on show the following section:—

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1. Flinty gravel; thin deposit unconformably overlying the limestone below.

2. Tufaceous white limestone (thin bed).

3. Hard grey crystalline limestone, 1·2 m.

4. Slope of sand and debris, doubtless covering soft marly beds.

On entering the depression at 98 kilometres a band of earthy reddish limestone with Bryozoa is crossed, this bed appearing to overlie the fissile sandy limestone already mentioned. From here a good view of the numerous limestone hills is obtained, the top beds of hard limestone showing out sharply from the lower sand-covered slopes; the beds show a stratigraphical depression here in addition to the eroded surface depression. The floor of the depression is covered with sandy gravel and Ostrea shells; an examination of the left scarp, about 3 kilometres after entering the hollow, showed the following succession of beds (total height of section 20 metres):—

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1. Hard white limestone with numerous shell-casts and containing some shaly layers, 3 m.

2. Debris-covered slope of softer beds with Ostrea shells, 16 m.

3. Red earthy limestone with shells at base of hill.

One of the hills within the depression, to the left of the track about 6 kilometres further on, showed in a face of about 28 metres the following beds:—

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1. Hard white limestone, sand-eroded.

2. Brown fossiliferous limestone.

3. White limestone with many small fossils.

The slopes of this hill were covered with large black Ostrea shells.

The floor of the depression further west showed limestones of varying character, frequently highly fossiliferous. Beyond the depression the ground passed over was mainly white limestone, strewn with large sharp angular flints, and many spheroidal flint-masses derived from the limestones. The surrounding hills show that we have here two white limestones with brown beds between, the floor and the hillcaps being white, while the feet of the hills are brown.

The plateau-rock near the great belt of sand-dunes is a hard white limestone with large Conidæ. Just beyond the dunes this rock is very siliceous, the exposed surfaces showing a smoky-black colour; the rock is however quite white on fracture. The hills rising from the plateau here consist entirely of limestone, beds of white chalk alternating with harder yellowish and brown limestones, in which no fossils were noticed. Further on the plateau rises, so that at the entrance to the depression the surface is formed of the same brown limestone-beds which are seen in the hills behind. The hills within the oval depression here are composed of alternations of chalky with harder limestones. The narrow ridge which separates the depression just described from the oasis-depression is of very hard horny siliceous limestone.

On the descent into the oasis the following beds are passed through:—

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1. Very hard yellowish and reddish-brown siliceous limestone, in part crystalline.

2. Fissile sandy limestone.

3. Soft yellow ochreous marly limestone.

4. Greyish-white chalky limestone, with ferruginous layers.

5. Sand-covered slope, mainly consisting of clays.

It seems probable that the entire mass of the limestones forming the surface of the plateau are Eocene, occupying an horizon in and below that of the Mokattam series. That the fissile sandy limestone and calcareous grit cannot be the equivalent of the Post Eocene sandstone deposits encountered on the road from Maghagha is proved by their being intercalated in the Eocene limestones of the plateau.

The return journey from Baharia Oasis to Minia was made, as already mentioned, across the open desert, not following any road. The starting-point was the point on the southern scarp of the oasis, where the Farafra road leaves Baharia. Our observations give for the position of this point lat. 27° 46′ 13″ N. long. 28° 32′ 47″ E. of Greenwich; height above sea level, 247 metres. The course was shaped so as to reach the village of Nasl Nadiub Lengat, whence the outward traverse had started, so as to give a closed polygon of survey-lines. The following topographical and geological notes were taken on the journey.

The first 2½ kilometres of the way, going about S.S.E., lay over a plateau of sandy limestone, often mammilated and strewn with limonite-fragments. Sand-dunes of small size were passed on the left. An ascent was then made of some 35 metres on to a flat-topped ridge, consisting of white and yellow marls and clays, capped by a horizontal bed of hard brown calcareous grit, passing into brown crystalline limestone with calcite shell-casts. On this ridge, which is about 600 metres in width at the place seen, a turn was made so as to go almost due east. The descent from the ridge on the other side is on to a plain strewn with whitish-brown laminated and mammilated limestone and some limonite, and from the plain rise hills showing the same structure as the ridge just crossed. A camel-road running south was crossed 7 kilometres from the starting-point, and beyond this, the ground having gradually risen to the level of the brown calcareous grit, we came among numerous low hills; these consist of white chalk beds, capped by sandy greyish limestone and then by thick beds of harder greyish-white limestone, weathered grey on the surface. No fossils were seen here, but continuing the journey east, over uneven ground of white and greyish limestone of considerable hardness, a small hill was met with, at about 12 kilometres from the starting-point, and found to consist of limestone with Nummulites, and these foraminifera were found in great abundance a little further on. The finding of these forms, so distinctively Eocene, is important as showing that whatever the age of the limestones at the actual edge of the south part of the oasis may be, the beds forming the plateau only a few kilometres east of the oasis are, like those which form the top of the northern scarp, of undoubted Eocene age. The nummulites were visible in the rocks of the plateau till about 17 kilometres from the starting-point, none being noticed further on till the neighbourhood of the great sand-dunes was reached. At 25 kilometres a slight depression containing numerous hills of white chalk was entered. The floor of this depression, 267 metres above sea-level, is strewn with fragments of crystalline calcite, probably derived from veins or druses in the chalk. The beds here dip slightly to the south. About 3 kilometres further on the beds dip about 5° E.S.E., so that higher beds were come on; the dip however soon diminished. At 29 kilometres the plateau rock consisted of porous siliceous limestone, generally white, but in places yellow, closely resembling that found capping the scarp in the northern parts of the oasis. The march was continued over white limestones of varying hardness, with flints and fragments of chalcedony on the surface, and numerous low limestone-hills. At 36 kilometres a chalky area was entered on, covered with countless small rounded hills of chalky limestone; these hills, of which there are literally millions, cover the ground like haycocks in a field; they are generally about 20 metres high, and up to 100 metres in diameter. No fossils were seen in the rocks. At 70 kilometres the hills began to get smaller, becoming presently mere chalk-mounds. A slight depression, about a kilometre wide, with larger chalk hills, was crossed at 73 kilometres, beyond which was a long stretch of flat ground composed of snow-white limestone, chalky to fairly hard, unfossiliferous, with thin siliceous bands. At 83 kilometres occasional low limestone hills were seen on ground otherwise fairly level, strewn with flints. A camel-road going south-east was crossed at 77½ kilometres. At 92 kilometres numerous small gasteropod casts were noticed in the chalk, but no other fossils. The plateau further on was seen to be formed of a hard thin bed of siliceous limestone, with chalk below; it shows occasional depressions with low hills within them. At 103 kilometres the great belt of sand-dunes running N.W.-S.E. was entered on. Close to the dunes and in the interspaces between them the plateau-rock is hard semi-crystalline white to brownish limestone, with nummulites and small gasteropod-casts. The sand contains a good deal of calcareous matter in addition to the grains of quartz. The dunes have a total width of about 3½ kilometres, some of them are of great height, and the passage with heavily laden camels is not without some difficulty.

Beyond the dunes the limestone is frequently siliceous, weathered smoky-grey on surface, and crowded with nummulites; the surface of the ground is generally sandy and flint-strewn. At 113 kilometres a narrow band of highly silicified, superficially blackened, limestone is crossed. This band, which is only a few centimetres broad, running north and south, stands up like a vein above the plateau, and is evidently caused by infiltration of siliceous solutions in a crack. In the silicified part of the limestone here the fossils can be easily seen; they are chiefly corals. Further on, the plateau consists of hard semi-crystalline and horny white limestone in which fossils are not seen.

At 123 kilometres the course, hitherto nearly eastward, was changed about 30° to the north, over the same hard semi-crystalline limestone, with hillocks showing alternations of soft chalky beds with harder ones. Some large flat-topped hills passed at 130 kilometres consist of horizontal limestone-beds, the lower ones being chalky, the upper ones hard, grey, and somewhat porous. Beyond this small rounded flints are seen on the plain, and these continue, increasing in number, till a low plateau in front is reached. At 134 kilometres a broad camel-road going south-east was crossed, and at 135 kilometres the scarp of a higher plateau was ascended. The lower plain has an altitude of 127 metres above sea-level, the top of the plateau being some 70 metres higher; the ground however rises gradually before reaching the escarpment, so that the actual rise at the scarp is only about 40 metres. The beds passed through on the ascent are—

Top.

1. Gravels of rounded flints and pebbles, thin covering.

2. White chalk, 2 metres.

3. Earthy limestone, 60 centimetres.

4. Red and white clays and marls, about 30 metres.

5. Sandy limestone, 20 centimetres.

6. Clayey limestone, 15 centimetres.

7. Sandy limestone, 60 centimetres.

8. Limestone conglomerate, 1 metre.

9. Red and yellow clays at base.

These beds appear to dip slightly eastward. No fossils were seen.

The top of the plateau is a huge level gravel-plain, with white chalky limestone showing through occasionally. Sometimes this rock shows a loose tufaceous texture; at other places it is sandy and fissile, and now and again it encloses small pebbles. A broad camel-road going south-east was crossed at 145 kilometres, and another in the same direction was crossed at 157 kilometres. At 162 kilometres, the gravelly ground having gradually fallen to 179 metres above sea-level, a turn so as to take again an eastward course was made, and a long stretch of gently undulating gravelly ground, with white limestone showing through in small patches, was traversed. A camel-road going east was crossed obliquely at 185 kilometres. At 196 kilometres, low gravel-covered hills of some extent were passed. The pebbles range up to 10 or 15 centimetres in diameter, and are well-rounded. In the lower part of one of these hills, sandy chalky limestone is seen cropping out through the gravel which covers the slope. Then a little further on are other low hills of white and grey nummulitic limestone, only thinly sprinkled with pebbles and sand. Some of the beds here contain cylindrical nearly vertical holes, one being measured and found to be 8 centimetres diameter and 45 centimetres deep.

Beyond the hills just mentioned is a further stretch of gravel, till at 199 kilometres a broad low ridge of white and creamy limestone, crowded with large nummulites (N. gizehensis) is reached. The beds of this ridge dip slightly west. The hollows of the ridge are full of blown sand. Beyond is a flat depression, the floor of which is strewn with small nummulites (N. curvispira), and with Ostrea and other shells; then another small nummulitic ridge is crossed, after which comes some hard smoky-grey silicified limestone, with much sand on the surface. At 202 kilometres from the starting-point a slight descent was made from the limestone on to a shelving gravelly tract with some sand-dunes. Some 4 kilometres further on the wide belt of low sand-dunes fringing the cultivated area west of Minia was entered. This sandy tract has a width of about 4 kilometres; it contains some patches of grassy land with pools of water.

The village of Nasl Nadiub Lengat, at the edge of the valley-cultivation, was reached after covering 212 kilometres from the south point of the oasis, the march having occupied about 60 hours.

To summarise the geology of the area crossed in the traverse just described, it will be clear that although the beds which form the top of the scarp at the south end of the oasis are probably of Upper Cretaceous age, yet these beds are overlain by Eocene limestone with nummulites at a short distance (about 10 kilometres) east of the Baharia-Farafra road. It is probable that the entire stretch of limestone-plateau between this point and Minia is Eocene, nummulites being recorded both from near the centre of the tract and from the edge of the desert near Minia. The softer chalky beds traversed appear stratigraphically lower than the Nummulite-limestone, and would seem to correspond to the chalky-limestones with Operculina libyca and Lucina thebaica which occur so constantly near the base of the Eocene in Kharga Oasis. The gravels, as already remarked in referring to the Minia-Baharia road, are of uncertain age, but are certainly Post-Eocene. The sand-dune belt crossed near the centre of the tract is the same as that crossed on the outward journey from Minia, and extends for a great distance north and south.

The road from Baharia to Farafra, traversed by Cailliaud in 1820, and by Jordan in 1874, was taken by a party of the Geological Survey in proceeding to Farafra after surveying the west side of Baharia. The start was made from the same point as the return traverse to Minia, viz., the point of ascent of the Farafra road at the south scarp of Baharia (lat. 27° 48′ 13″ N., long. 28° 32′ 49″ E. of Greenwich), and the general course taken was in a direction 30°-40° west of south. A second, almost disused, road from Baharia to Farafra ascends the western escarpment from the depression 3½ kilometres further north, follows a narrow plateau at the base of the chalk escarpment and joins the main road some distance south of the extreme end of the oasis-depression.

The main road after ascending the scarp at the extreme south end of the depression, at the point mentioned, proceeds at first in a direction about 30° west of south, over a limestone plateau, with sandstones and clays below. After 4 kilometres hard concretionary grey sandstones are noticed, and 3 kilometres further on a small hill of hard false-bedded grey sandstone is passed. The escarpment of the White Chalk now approaches within 2 kilometres of the road on the right hand, on the left being slightly further away. These escarpments run parallel with the road for some 5 kilometres, forming a large bay, until at 12½ kilometres the road passes through a narrow pass with the cliffs of white chalk quite close on either side. Almost immediately the cliffs again recede, forming a small bay opening into another still larger at 14½ kilometres. At this point an isolated chalk stack, with great masses of fibrous calcite at the base, is passed, and this hill makes a convenient point for a survey-station. Several more isolated hills are now passed and then the chalk scarps on either side close up and join, the road passing up the escarpment at the end of the bay and gaining the summit of the white chalk at 20½ kilometres. The beds forming the plateau between the end of the oasis-depression and this escarpment of white chalk belong to the middle series of the Upper Cretaceous, the “variegated clays and sandstones,” fully described in Chapter V.

From the top of the white chalk escarpment the road continues in a well-maintained direction of about 40° west of south, over a more or less level gravelly plain with outcrops of hard crystalline limestone or chalk. Another, less used, road to Farafra, via the bay to the north-east of Ain el Wadi (in Farafra Oasis), probably branches off about this point. At 35 kilometres a small hill of siliceous limestone is passed and the chalk forms a slight escarpment a little way to the left.

About a kilometre further on a ridge of dark brown ferruginous sandstone is crossed and almost immediately afterwards, at 49 kilometres, the road descends through snow-white chalk cliffs into the depression of Farafra. The chalk forming the cliffs weathers in places to a smoky-black colour. At the bottom of the descent, which is gentle and presents no difficulties, an isolated hill occurs on the left and from this the dark clump of palms of Ain el Wadi is plainly visible bearing 9° west of south and distant about 16 kilometres. From Ain el Wadi to Farafra village is another day’s march of 43 kilometres, the road bearing about 35 west of south, but for details the reader is referred to the report on Farafra Oasis. With regard to the geology of the road across the plateau separating Baharia and Farafra, the age of the beds first passed over has already been mentioned. After rising on to the white chalk the surface of this formation is followed right up to the descent into Farafra. Although occasional crystalline limestones are crossed, these, with the surface accumulations of flinty material, are only skin deep and the former probably represents the upper part of the chalk itself. No Eocene beds were observed, and it is extremely doubtful if any exist; in the latter case they would be patches of Operculina-nummulitic limestone from the base of the Esna Shales, as this limestone is sometimes left capping the surface of the white chalk after complete denudation of the shales above, as in the bay to the north-east of Ain el Wadi. We thus see that the Cretaceous of Baharia is continuous with that of Farafra and that the intervening desert is not formed of the Nummulitic limestones of the Eocene as formerly supposed and shown on the Rohlfs Expedition map.

Besides the routes already mentioned, there are several other roads connecting Baharia with Siwa Oasis, the Fayum, and the Nile Valley. Of the principal of these we have a fairly accurate knowledge from the records of scientific travellers, such as Jordan and Ascherson, and it may be well to mention briefly the chief points concerning them.

The road from Siwa was traversed by Jordan in 1874, the march occupying ten days. Leaving Siwa (N. lat. 29° 12′ 0″, long. 25° 31′ 0″ E. of Greenwich, altitude 25 metres below sea-level), the road follows an east-south-east course for about 80 kilometres; it then turns slightly more southwards, rounding the corner of the plateau (Pacho Mt. of Rohlfs) and afterwards passing through the deep depressions of Aradj (- 70 m.) and Uttiah (- 20 m.) to the south side of Lake Sittra (- 25 m., N. lat. 28° 42′ 40″, long. 27° 4′ 23″ E. of Greenwich, 170 kilometres distant from Siwa). From Sittra an easterly course is taken for some 52 kilometres, when another slight turn to the south is made, the oasis of Baharia being entered by descending the scarp some 3 kilometres slightly north of west of El Qasr. Between Sittra and the edge of the oasis the ground, which is of nummulitic limestone, rises gradually but steadily, the level at the edge of the oasis being 194 metres above sea. The distance from Sittra to El Qasr is about 180 kilometres, making the total distance along the route taken from Siwa about 350 kilometres.

The road from the Fayum to Baharia, taken by Belzoni in 1819, Pacho in 1823, and Ascherson in 1876, has a total length of about 240 kilometres, and occupies some six days in marching. Leaving Medinet el Fayum the road proceeds south-west via Gharag to Wadi Rayan (29 m. below sea-level, about 75 kilometres from Medinet el Fayum) where a supply of water is obtainable from several different springs. From Ain Rayan the road proceeds south-west over a rising nummulitic limestone plateau, crossing the so-called Bahr bela Ma a little north of the Maghagha-Baharia road. At “El Bahr” (100 kilometres from Ain Rayan) a turn is made to the W.S.W.; the sand-dunes of Abu Moharik are crossed a little further on, and the oasis is entered at the northern extremity by the same “agaba” as that taken by the Maghagha road. Within the oasis the road branches as already described, the west branch leading to El Qasr and the east one to Zubbo.

Another route making use of the same point of entry into the oasis as that just described is marked on Ascherson’s map as coming from Bahnessa, a large village on the Bahr Yusuf, near the western edge of the Nile Valley. This road, which is some 190 kilometres in length, leads almost due west over a monotonous plateau till near the oasis, where it joins the roads from the Fayum and Maghagha.

The road between Baharia and Samalut, traversed on his return journey by Ascherson in 1876, appears to be the shortest connection between the oasis and the Nile Valley. Its course is due west, and its total length to Mandisha about 180 kilometres. Leaving Samalut the cultivation is crossed via Mangatin to Rubi; this latter village is on the edge of the desert, about 5 kilometres west of Samalut. The road proceeds over a monotonous rocky and gravelly plateau, crossing the great sand-dune belt of Abu Moharik about 122 kilometres west of Samalut, and entering the oasis near Ain Gelid by the same descent as that used by the Survey party from Minia. The journey from Bawitti to Samalut occupied Ascherson four days.

Still another road from the Nile Valley, likewise entering the oasis near Ain Gelid, is marked on Ascherson’s map as coming from Delga, a village near the west edge of the valley-cultivation. This road has a N.N.W. course, and a total length from Delga to Mandisha of about 190 kilometres. It crosses the sand-dunes of Abu Moharik about 130 kilometres from Delga, i.e., about 40 kilometres before reaching the edge of the oasis.

Several other roads start from points still further south, such as Der el Maragh, Beniadi, Assiut, etc., and most of the villages along the west side of the Nile Valley between Assiut and the Fayum have branch tracks which join the main roads at different points.

* * * * *

(Recent Geological Discoveries in the Nile Valley and Libyan Desert, London, 1900.)]

These gravels were examined and mapped in the Survey of the Nile Valley in 1896. (H. J. L. B.)]