* * * * *
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.[17]
[Sidenote: Road from Feshn and Maghagha to Baharia.]
_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.[18] 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[19] and Ascherson[20] 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.[21]
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.
[Sidenote: Geology of the Feshn-Baharia]
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.[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.
{ 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.
[Sidenote: Road from Minia to Baharia.]
_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.
[Sidenote: Geology of the Minia-Baharia Road.]
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[24] 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):—
_Top._
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:—
_Top._
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:—
_Top._
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):—
_Top._
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:—
_Top._
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:—
_Top._
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.
[Sidenote: Traverse from south end of Baharia to Minia.]
_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[25] 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.
[Sidenote: Baharia-Farafra road.]
The road from Baharia to Farafra, traversed by Cailliaud in 1820,[26]
and by Jordan in 1874[27], 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.[28] 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.[29]
[Sidenote: Other Roads.]
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[30] 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.
* * * * *
[Footnote 17: For remarks on the surveying of desert roads, and on
the possibility of traversing the open desert, see BALL Kharga Oasis
(Reports of the Geolog. Survey for 1899, Part II) Cairo, 1901, p. 16.]
[Footnote 18: For details of these hills and Wadi Muailla see
BEADNELL, _The Topography and Geology of the Fayum, etc._, Survey
Dept. P. W. M. Cairo, (in the press).]
[Footnote 19: _Op. cit._ p. CXXXVI.]
[Footnote 20: See Schweinfurth in “Pet. Mitt.” 1876, p. 265;
also Ascherson in “Zeitschrift d. Gesellschaft für Erdkunde”
zu Berlin, 1885, p. 115.]
[Footnote 21: BEADNELL, _Découvertes Géologiques Récentes dans la
Vallée du Nil et le Désert Libyen_, compte rendu, VIIIe Congrès
Géologique international, 1900; Paris 1901, p. 847.
(Recent Geological Discoveries in the Nile Valley and Libyan Desert,
London, 1900.)]
[Footnote 22: For a brief description of these deposits see
_Découvertes Géologiques_, etc., pp. 863-865.]
[Footnote 23: _Geolog. Mag._ Jan. 1900, No. 427, p. 18, and _op. cit._
(_Découvertes géologiques_), p. 847.]
[Footnote 24: BALL. _Kharga Oasis_, p. 23, Cairo 1900.
These gravels were examined and mapped in the Survey of the Nile
Valley in 1896. (H. J. L. B.)]
[Footnote 25: Jordan’s position for this point is approximately
lat. 27° 46′ 20″ N., long. 28° 36′ 20″ E. of Greenwich,
altitude 193 metres above sea-level.]
[Footnote 26: _Voyage à Méroé_, etc., vol. 1, p. 196.]
[Footnote 27: _Physische Geographie der libyschen Wüste_, p. viii.]
[Footnote 28: BEADNELL, _Farafra Oasis, its Topography and Geology_,
Geol. Surv. Egypt Report, Pt. III, Cairo, 1901.]
[Footnote 29: _Découvertes Géologiques Récentes_ etc., p. 850.]
[Footnote 30: See the geological map accompanying Zittel’s _Geologie
der libyschen Wüste_, Cassel 1883.]