Section X.—MIDDLE EOCENE (PARISIAN).

A.—Wadi Rayan Series.—(Nummulites Gizehensis Beds).

(A.I.e. Schweinfurth, I.b. Mayer-Eymar,[36] Lower Mokattam of Cairo).

Beds of this group are chiefly found in the south of the depression. The wadis Rayan and Muêla, as already shown by Schweinfurth and Mayer-Eymar [37], are cut out in clays and limestones of Lower Mokattam age; the upper beds of limestone, containing among other fossil [38] numerous examples of the large Nummulites gizehensis, form the greater part of the floor of the depression west of the Fayûm cultivation, stretching from Jebel Rayan to the foot of Gar el Gehannem,[39] 28 kilometres west of the western end of the Birket el Qurûn ([Section XX]). Near the latter hill examples of N. gizehensis of inordinately large size occur.[40]

At the conical hill at the southern entrance to Wadi Muêla the following beds were noticed:—

Top of hill.
1.	Hard white limestone with smallnummulites, Lucina, Callianassa, and echinids. Saltoccurs in thin deposits along joint-planes. The lower part of thisbed is largely composed of small nummulites and bryozoa. Thisgenerally white limestone passes down into
2.	Brown, usually sandy, limestone withoysters and small nummulites. In it are intercalated thin beds ofgreenish brown sandstone and clayey sand with impressions ofbryozoa. Some of the brown sandy limestones are full of smallnummulites. Ostrea and Carolia numerous. The beds arenot constant, the clayey sandstones passing insensibly into sandylimestones.
3.	Softer beds with large nummulites,corals, Ostrea, Nautilus.
4.	Soft green and brown clays, withoccasional oyster-beds.

At the corner of the cliff 7½ kilometres N.N.W. of the monastery of Der el Galamûn, in Wadi Muêla, occur about 80 metres of hard white nummulitic limestones, with beds of argillaceous sandstone and sandy clays. Fossils are numerous and include nummulites of several species (N. gizehensis, etc.), Carolia placunoides, different species of Ostrea, with gastropods (among others Terebellum sopitum), bryozoa, etc. It is very noticeable that the nummulites, especially the small species, occur in remarkable profusion not only in the limestones but often in the clays.

The following section will give a good idea of the general alternations found in this area; it was measured at Jebel Rayan,[41] 24 kilometres west of the western end of the cultivation of Gharaq basin.

Top of plateau.		Metres.
1.	Hard snow-white limestone with occasionalnummulites passing down into hard highly nummulitic limestone;N. gizehensis, Ostrea sp., Lucina sp.,Mitra sp., and Carolia placunoides occur amongothers	31
2.	Vertical-faced bed of greenish clayeysands and sandy clays (glauconitic) with Carolia,Ostrea and Nummulites. Near top of bed there is muchgypsum. The nummulites in this bed are often collected together soas to form hard concretionary masses; these masses, by becomingmore numerous, finally form a hard bed of nummulitic limestoneintercalated in the clays near the top. The junction of the clayswith the limestone of Bed No. 1 is very irregular	16
3.	Greenish shelly sands and sandy clayeybands, interbedded with impure chalky nummulitic limestones withN. gizehensis, N. curvispira, and a third smallerspecies; Ostrea sp. This bed is much obscured by debris	11
4.	Hard slate-blue shales, weathering topaper-shales	2
5.	Brownish marls passing up into clays	2
	Limestone band largely made up of smalland large nummulites and echinids	1
	Glauconitic (?) and clayey sands andsandy clays, with Ostrea, Carolia, and nummulites,weathering with a vertical face. In some bands large numbers ofsmall and large nummulites lie embedded in every position, as iftossed about by currents during the process of becoming buried bysediment. Gypsum occurs in thin veins and often encloses thenummulites	36
6.	Hard markedly-white nummulitic limestonefull of N. gizehensis and other species (N.curvispira, etc.); the rock usually has a dark brown colourwhen freshly fractured. A shelly band rich in corals occurs ninemetres from the top. The upper part is more marly and lessnummulitic than the rest of the bed. Base invisible	30
	Total thickness of beds in the above section	129

Plate V.

ALLUVIAL DEPOSITS OVERLYING MARLY LIMESTONES (RAVINE BEDS) IN EL WADI, RAVINE NEAR QASR GEBALI.

The following is a section of the beds exposed in Wadi Muêla compiled from a paper by Mayer-Eymar on this oasis:—

Top.			Metres.
Parisian.	Id.	White siliceous cavernous limestone withLucina globulosa, Desh., Gisortia, Rostellaria, EscharaDuvali, Michelin., (Probably ≡ bed No. 1 of our J. Rayansection)	10
		Greyish-yellow marl, rich in places withOstrea Gumbeli, Pecten mœlehensis, May.-Eym., Vulsellachamiformis, May.-Eym., Velates Schmiedeli, Chemnitz, Cerithiumfodicatum, Pleurotoma, Borsonia, Fusus, Rostellaria,etc.	6
		Yellowish sandy marl, with smallnummulites.

	Ic.	Yellowish marls, divided by one or twobands of red clay, with Nummulites gizehensis	7
		Hard bedded clay	1
		Vari-coloured gypseous marls	4
		(Probably ≡ beds 2, 3, 4 at J. Rayan).

	Ib.	Very hard, rich greenish-grey, siliceouslimestone with N. gizehensis, Pecten corneus, J. Sow., andLucina (L. consobrina, Desh., and L. Defrancei, Desh.).	4 to 5
	Ib.	(Probably ≡ upper part of bed 5 at J. Rayan.)

There is a considerable difference in thicknesses between the above section and that of Jebel Rayan. Our heights agree closely with those of Schweinfurth, so that it is probable that Mayer-Eymar is in error, notwithstanding his challenge of Schweinfurth’s figures in the paper mentioned.

B.—Ravine Beds.

The beds of this series, consisting of gypseous clays, clayey marls, and white marly limestones, are met with bordering the cultivation on the east, west and north sides; they pass under the alluvial soil of the cultivated land and are frequently seen in the bottoms of canals, and especially in the deep ravines known as El Bats, and El Wadi (Plates [III] and [V]). The relation of these beds to the Rayan series below is well seen at the prominent outstanding hill Gar el Gehannem ([Fig. 2]); here the plain to the east and south is formed of the uppermost member of the Wadi Rayan series, a limestone full of Nummulites gizehensis. In the hill itself the latter is directly overlain by gypseous and glauconitic sandy clays and marls, with hard intervening beds of yellowish, often marly, limestone. The upper beds consist of alternating clays, sandy limestone and sandstone, at the top being a thick bed of the latter passing up gradually into the sandstones of the Birket el Qurûn series. The following is the detailed section:—

Summit of Gar el Gehannem.		Thickness in metres.
1.	Hard yellow and white limestone crowdedwith shells, chiefly large individuals of Caroliaplacunoides and Ostrea Fraasi. Numerous nummulites inupper part	Lower beds of Qasr el SaghaSeries (45 metres)	25
2.	Limestone full of Turritellacarinifera, Ostrea Clot-Beyi		1
3.	Brown clays		6
4.	Shelly limestone with Carolia,Turritella, Ostrea, Cardita and Qerunia(Hydractinia)		1
5.	Greenish clays		6
6.	Nummulitic limestone with Carolia,Qerunia and four species of Turritella		1½
	Light blue clays		2
7.	Light green and brown sandstone withirregular concretions		2½

8.	Brown shelly limestone full of Caroliaplacunoides, Ostrea Reili, O. Fraasi,Turritella, Balanus and nummulites	Birket el Qurûn Series (50 metres)	2
9.	Yellow sandstone with bands of shellylimestone crowded with nummulites, oysters, etc. Near top casts ofCardita, Carolia; also Cerithium,Teredo, Ostrea, Pecten, Pinna, andechinids. Calcareous concretions near base		18
10.	Clays with much gypsum		6
11.	Yellow sandstone with Balanus.Bands crowded with two species of nummulites and occasionaloysters. In places the foraminiferal bands become highlycalcareous. Below similar, with hard compact grey bands andoccasional fish-spines and teeth		24

12.	Similar to above, with numerous casts ofCardita, etc., and small Ostrea	Ravine Beds (10 metres)	24
	Argillaceous sandstone with thickstockwork of gypsum and calcareous nodules		6
13.	Light yellow, brown, and greyish gypseousclays		3
14.	Yellow-brown sandstones and sandylimestones, often argillaceous. Fish-scales.
	Brown clays
	Yellow-white marls and marlylimestone		5
15.	Hard light yellow shelly limestone, inpart marly, in part sandy		10
16.	Ochreous-yellow, grey, and white claysand marls with gypsum		9
17.	Hard yellow-white shaly marl withnumerous shell-impressions; much gypsum		3
18.	Yellow marly clays; soft yellow andgrey-brown clays, dark sandy glauconitic, yellow, and black, clays.Zeuglodon remains fairly common. Shell impressions. Muchgypsum
	Fairly hard yellow-white glauconiticmarl		10
Marly limestone withNummulites gizehensis forming top of Rayan beds.

Fig. 2.—Section at Gar el Gehannem, showing the relation of the Wadi Rayan Series to the Ravine Beds.

The clays, marls, and limestones of the Ravine beds are generally found to contain fairly numerous shell-impressions, including Nucularia sp., Leda sp., Cardita sp., Corbula aff. pixidicula, Lucina sp., Oudardia ovalis, Desh., Tellina tenuistriata,[42] numerous small fish-scales, and occasional large teeth of sharks; while the skeletons of the toothed-whale Zeuglodon Isis are fairly common, although usually in poor preservation.

In the ravine of El Bats, about one kilometre west of Sêla, these beds (5-6 metres thick) are seen unconformably overlaid by 12 metres of false-bedded gypseous sands and clays passing up into the superficial cultivated loam. The junction of these alluvial deposits and the underlying Eocene is distinctly unconformable and an intervening pebble-bed is occasionally present ([Fig 3]).

In the large ravine known as El Wadi, which traverses the west side of the cultivation of the Fayûm, these beds are frequently well exposed; their lithological characters remain very constant. Here, as in El Bats, they are unconformably overlain by a varying thickness of Pleistocene and Recent clays. Their surface, a plain of subaerial denudation, represents the original floor of the depression before the entry of the sediment-carrying water from the Nile Valley through the Lahûn gap; its irregularity is seen in [Plate V.]

The plain bordering the cultivation to the east of Sêla and Rubiat likewise consists of these same white marls with fish-scales, etc.; they pass regularly under the cultivated land. Shaly marls, gypseous clays, and chalky limestones of the same age are seen in, and to the south of, the railway crossing the desert between Sêla and Medum. Eastwards they stretch into the Nile Valley, being found exposed along the desert-edge bordering the cultivation at Medum, Nawamis and Masaret-Abusia.

RECENT ANDPLEISTOCENE				1. Marsh and poorly cultivated land.
				1a Cultivated loam.
				2. Sands and clays, with gravelly bands;often concretionary and gypseous beds.
				3. Pebble-bed marking unconformablejunction.

MIDDLE EOCENE	⎱ ⎰	Ravine Beds	⎰ ⎱	4. Gypseous saliferous marly clays, whitemarls and limestone with fishscales and Tellina Corbula,etc.

Fig. 3.—Sketch-Section across El Bats, 1 kilometre West of Sêla.

The same beds are exposed immediately to the east of the village of Sersena, midway between Sêla and Tamia. They are again well seen in the ravine below the last named village, and forming the narrow strip of the desert projecting into the cultivation as far as the northern end of the Tamia lake; they also occur on the shore of the latter at El Tuba, about 2 kilometres south of the village. At Tamia their exposure measures 25 metres in thickness.

At various points along the north side of the Birket el Qurûn exposures of this series occur, the beds forming the lower sloping part of the cliffs overlooking the lake, as well as the base of the island “Geziret el Qorn,” although only the upper beds are visible above the water of the lake. Both here and along the northern shore of the lake they are for the most part hidden by the high level recent lacustrine clays, but where occasionally exposed their identity is certain, the characteristic small brown fish-scales being abundant, besides occasional teeth, with shell-impressions of the different genera enumerated above.

Plate VI.

ESCARPMENT OF THE BIRKET EL QURUN SERIES NEAR THE WESTERN END OF THE LAKE.

At the western end of the lake the Ravine beds form the lower part of the cliff as well as the plain to the south; the underlying Nummulites gizehensis limestone not being exposed. The series consists of some 45 metres of white and grey shaly marls with harder bands of siliceous limestone intercalated throughout, one of which usually forms the uppermost bed. It is, in fact, the development in places of one or other of these hard beds of limestone near the top of the series that gives rise to the bold promontories, or horns, which occur on the north side of the Birket el Qurûn.

The greater part of the marls and clays met with from 18·5 to 112·5 metres below the surface in the boring at Medinet el Fayûm in all probability belong to the Ravine beds.

The maximum thickness of this series is 70 metres, measured at Gar el Gehannem.

C.—Birket el Qurun Series (Operculina-Nummulite Beds).

The above designation is convenient and applicable to these beds, which form the escarpment immediately overlooking the lake on the north side throughout its length.

The group includes all the beds between those last described and the well-marked Qasr el Sagha series, homotaxial with the Upper Mokattam (the brown beds) of Jebel Mokattam, near Cairo. It thus appears to be the equivalent of the upper part of the white beds (quarried limestones) of the Mokattam section, although the lithological characters are entirely different, the massive limestones of Jebel Mokattam being represented in the Fayûm by an arenaceous and argillaceous series, deposited probably in water of far less depth. Where the different members of this series are well exposed certain beds are found to be characterized by the abundance of two foraminifera, the one a small thin-shelled Operculina (O. discoidea)., and the other a small thick nummulite.[43] The tests of these foraminifera sometimes make up entire bands of rock. In addition, the series includes certain beds which at times become very fossiliferous, and contain a well-preserved molluscan fauna.

The series is well seen in the desert separating the Fayûm from the Nile Valley; on the south-east and east sides of the former; along the northern boundary of the cultivation and the Birket el Qurûn; and westwards in the cliffs to beyond the outlying hill-mass of Gar el Gehannem.

The following section was measured on the south-west of the Fayûm, from Ezba Qalamsha (on the confine of the cultivation) to the ridge summit 5 kilometres to the south-east.

Top.			Metres.
	Summit of ridge 5 kilometressouth-east of Ezba Qalamsha.
	Pliocene Raised Beach withoccasional Ostrea cucullata, Born., made up of gravels withblocks of limestone.
Birket el Qurun Series.	1.	Ochre-coloured calcareous sandstone andsandy limestone crowded with foraminifera (NummulitesFraasi, etc.), Ostrea, etc.	38
	2.	Sandy limestone, largely made up offoraminifera (Operculina discoidea ?)	2
	3.	Sandy shale	2
	4.	Sandstone, partly calcareous, with muchgypsum	3
	5.	Calcareous sandstone with concretionaryweathering	17
	6.	Shale with gypsum	2
	7.	Calcareous sandstone	4
	8.	Shale with gypsum	2
	9.	Calcareous sandstone, hard andyellowish	2
	10.	Gypseous shale with numerous small shells(Tellina sp.) passing down into sandy limestone. (This bedis the uppermost member of the Ravine beds)	6
		Total thickness	78
Base, cultivation level.

To the north of the Lahûn pyramid the beds agree generally with the above. The following are the chief divisions here:—

Top of Hills.		Metres.
	Gravel Terrace (Pliocene) 22 metresthick.
1.	Calcareous sandstone and sandy limestonesfull of nummulites; also Ostrea, etc.	31
2.	Ochre-coloured calcareous sandstone orsandy limestone, often crowded with Operculina discoidea andsome Nummulites Fraasi, etc.	12
3.	Sandy limestone with small foraminiferaat top and some shells. The upper part of this bed has beenquarried	20
4.	Shales and shaly limestone; gypsum	—
	Total thickness	63

The foraminiferal sandy limestones of this series are seen at points in the desert bounding the eastern margin of the cultivation, notably east of Sersena and at the top of the hill 15 kilometres north-east of Rubiat.

The following section was measured at the prominent hills 17 kilometres 28° N. of E. (magn.) of Tamia:—

			Metres.
1.	Greyish laminated sandy clays withgypsum; Ostrea band near top		7
2.	White sandy limestone with numerous badlypreserved Ostrea, Pecten, and otherlamellibranchs		1
3.	Dark-brown clayey sands with gypsum andgrey sandy clays with obscure plant-remains. OccasionalOstrea		14
4.	Hard, white, sandy limestone withnumerous Ostrea at top; soft clays with gypsum		1
5.	Greenish and brownish sands and sandyclays with band of sandy limestone near top	⎱ ⎰	14
6.	Greyish-brown, impure, sandy limestoneweathering into large globular concretions. Shell impressions	⎱ ⎰	14
7.	Sandy clays and marls alternating withimpure limestones; much gypsum. Occasional fish-remains and smalloysters	⎱ ⎰	22
8.	Greenish sandy limestone with traces ofshells	⎱ ⎰	22
9.	Finely laminated grey-brown clays withblack carbonaceous matter and fish-remains; saliferous		3
10.	White sandy limestone		1
11.	Soft yellow sandstones, etc.	⎱ ⎰	7
12.	White marls with fish-scales, etc.; basenot seen. (This bed, and possibly also 9, 10, 11, should bereckoned as belonging to the Ravine beds)	⎱ ⎰	7
	Total thickness		70

In the north of the Fayûm the series is characterized by the presence of one or more very constant well-marked beds of hard calcareous sandstone, which almost invariably weather into huge globular masses. These masses should be regarded as huge weathered-out concretions, rather than as water-rounded blocks, although no doubt in many cases their roundness has been increased by the action of the waters of Lake Moeris as the level of the latter gradually fell, and possibly still earlier during the invasion of the Pliocene sea; from the latter time also may date the millions of parallel vertical borings with which these and other exposed rocks are often perforated. In the various places where one of these beds forms the present surface of the desert the concretions may be seen in different stages of exposure, from the initial, where only just the tops are laid bare, to the final stage where the globes are left completely weathered out, as seen in the illustration ([Plate VII]). The appearance of the desert when covered for many square kilometres with thousands of these blocks is more easily imagined than described.

The lower beds of the Birket el Qurûn series form the island Geziret el Qorn, and consist of clays and sandstones containing a considerable number of organic remains. These beds were collected from and examined by Schweinfurth [44] in 1879, the mollusca being subsequently described by Mayer-Eymar,[45] while the vertebrate remains, which included cetacean bones and numerous fish-teeth, were submitted to Dames.

The following species were determined by Mayer-Eymar, who indicated that the fauna as a whole had a Bartonian aspect [46]:—

Upper Bed.

Ostrea plicata, Defr.
Arca Edwardsi, Desh.
Lucina pomum, Duj.[47]
Lucina cfr. tabulata, Desh.
Cardium Schweinfurthi, May.-Eym.
Cytherea Newboldi, May.-Eym.
Tellina pellucida, Desh.
Mactra compressa, Desh.
Corbula pyxidicula, Desh.
Calyptræa trochiformis, Lam.
Turritella angulata, Sow.
Ficula tricarinata, Lam.

Lower Bed.

Astrohelia similis, May.-Eym.
Goniastræa cocchii, d’Achiardi.
Heliastræa acervularia, May.-Eym.
Heliastræa Ellisi, Defr. (Astræa).
Heliastræa flattersi, May.-Eym.
Ostrea digitalina, Dubois.
Ostrea gigantea, Sol.
Ostrea longirostris, Lam.
Ostrea producta, Delb. et Raul.
Isocardia cyprinoides, Braun.
Turritella carinifera, Desh.
Turritella transitoria, May.-Eym.
Turritella turris, Bast.
Turbo Parkinsoni, Defr.
Pleurotoma, sp.

The cetacean remains, belonging to the genus Zeuglodon, were described by W. Dames,[48] who compared them with the American species Z. macrospondylus and Z. brachyspondylus, but did not then consider them to represent a new species; in a later publication,[49] however, the same author described similar but more complete remains, also collected by Schweinfurth (from beds belonging to our Qasr el Sagha series), as a new species, Z. Osiris. A considerable number of fish-remains from Geziret el Qorn are also described in the earlier publication. Although the difference in size of the bones of separate individuals was considered by Dames to be sexual, it seems probable that there are two distinct species of Zeuglodon, as the smaller type appears to have a much greater upward range than the larger [50]; both species, Z. Osiris, and Z. Isis occur in the Birket el Qurûn series, and a very fine mandible of the larger was obtained from these beds in the cliffs near the west end of the lake.[51] More recently a third species has been discovered by Stromer and described under the name of Z. Zitteli.[52]

Fig. 4.—Profile of beds of Geziret el Qorn.

1. Hard brown sand-rock with large concretions of weathered globular sandstone on the summit; ferruginous nodular bands containing shell-casts occur near top. 2. Soft gypseous clays with bands of sand-rock and sandstone with Ostrea, Cardium Schweinfurthi, Turritella, corals, Zeuglodon, chelonian and fish-remains. 3. Brown sand-rock. 4. Soft gypseous clays and harder brown sandstones. 5. White shaly marl with fish-scales; hard band at top and soft sandy shaly clays below.

The surface-slope is much less than shown in sketch and is generally covered by a deposit of lacustrine clays containing freshwater shells and fish-bones.

The accompanying profile (Fig. 4), measured during a hurried visit to the island for the purpose of correlating these beds with those of the mainland, shows the character of the lower beds of the Birket el Qurûn series at this point.[53]

Plate VII.

WEATHERED CONCRETIONARY SANDSTONE (BIRKET EL QURUN SERIES) ON NORTH SHORE OF LAKE NEAR GEZIRET EL QORN.

The upper beds of the Birket el Qurûn series in this part of the Fayûm are lithologically similar to those just described, consisting of alternating clays and sandstones, about 37 metres thick. They are, however, generally much richer in fossil remains, which are likewise usually better preserved than in the lower beds. Some of the brown sandstones of this series are literally crowded with perfect examples of many of the typical mollusca; and further west, near the end of the lake, foraminiferal bands again become noticeable. Near Dimê the escarpment of these and the lower beds is gentle and inconspicuous, but followed westwards it becomes a bold precipitous cliff, increasing in height towards the western end of the lake, where it is capped by the lower beds of the Qasr el Sagha series.

The following section was measured on the mainland [54] opposite the island Geziret el Qorn.

		Metres.
1.	Gypseous clays, separated by a band ofbrown sandstone crowded with white well-preserved shells, includingnumerous individuals of Plicatula polymorpha, Ostrea,Turritella and Lucina pharaonis. Large vertebrae ofZeuglodon Isis occur on this horizon further to thenorth-east	8
2.	Sandstones and gypseous clays. Althoughhere the sandstones are not hard or predominant, this bed isequivalent to the hard sandstone full of borings capping the plainbetween the ruins of Dimê and the top of the escarpment overlookingthe lake. Further north this bed often contains numerous Caroliaplacunoides and Ostrea	3
3.	Gypseous clays	3
4.	Clays, brown sandstones, and occasionalbeds of limestone, often very fossiliferous, containing OstreaReili, Carolia placunoides, Cardita Viquesneli,d’Arch., Lucina sp., Turritella pharaonica,[55]Clavelithes longævus, Qerunia cornuta, etc.,etc.	10
5.	Clays with fossils as in last bed, cappedby hard band of shelly sandstone	3
6.	Alternating yellow-brown sandstones andgypseous clays	10
	Total thickness	37
Bed with weathered-out sandstone concretions attop—upper bed of section at Geziret el Qorn.[56]

At the western end of the Birket el Qurûn the series is well marked, the sandstone beds forming the steep face of the bold precipitous cliffs which are so marked a feature at this end of the lake. The group has a thickness of some 50 metres and is overlain by the lower beds of the Qasr el Sagha series; it is more convenient here to give the entire section of the cliffs down to the base of the series under discussion:—

Top of Cliffs.				Metres.
1.	Hard grey sandstone and shelly limestonepassing up into calcareous sandstone (forming surface of plaindipping north).		Lower part (42 metres) of Qasrel Sagha Series.
2.	Impure sandstone with numerousfossils:—Qerunia cornuta, corals, Ostrea Reili, O.Clot-Beyi, Carolia placunoides, Plicatulapolymorpha, Cardita (? fajumensis) sp.,Clavelithes longævus, Serpula, etc.
3,	4. Clays with band of argillaceoussandstone. Septaria bed near base. Fish-remains.
5.	Earthy limestone crowded with OstreaClot-Beyi, O. sp., Plicatula polymorpha,Pecten sp., Lucina sp., Cytherea sp.,Turritella sp., Nonionina sp., Oliva sp.,Pleurotoma sp., Vermetus sp., Nautilussp.
6.	Thin-bedded clays, grey with yellowishband, sandy clays interbedded with soft whitish sandstones withsmall irregular concretions. Clays, gypseous and sometimescarbonaceous.
7.	Shelly sandstone, hard on upper surfaceand very fossiliferous (forms similar to Bed 9).
8.	Gypseous clays.
9.	Thin (·25 to ·5 metre) hard darkreddish-brown, very ferruginous, concretionary-weathering sandstonewith nummulites and Operculina and well-preserved examplesof Qerunia cornuta, Pecten sp., Pectunculussp., Venus sp., Cardita Viquesneli, Astartesp., Macrosolen Hollowaysi, Lucina sp., Naticasp., Cerithium sp., Clavelithes longævus,Voluta sp., Dentalium sp.			1
10.	Hard purplish clays			7
11.	Soft yellowish sandstone withOstrea sp., Cardita ægyptiaca, Lucina sp.,Turritella sp., and sharks’ teeth. Upper surface tends tobecome dark, ferruginous, and concretionary			1
12.	Purple clays, with strings of gypsum			6
13.	Soft light-yellow sandstones with hardershelly bands and occasional concretionary beds, forming verticalcliff-wall			17
14.	Grey and brown clays			18
Ravine Beds.		Total		50

In the cliffs west of the end of the lake the upper bed No. 9 continues highly fossiliferous and yields the most perfectly preserved molluscan remains to be found in the Fayûm and probably in Egypt.

A few kilometres east of the end of the lake a band of large globular concretions occurs in the thick brown sandstone forming the vertical face of the cliff. In many places the effect of weathering of these rocks is of some interest, numerous “earth-pillars” having been formed; these are largely the result of the action of blown sand, assisted by rain, the concretions being left capping pillars of brown sandstone, the sides of which are sculptured by the wearing action of sand. The curious perforate or cellular appearance which the weathered surfaces of this sandstone assume after long exposure are particularly noticeable in this neighbourhood and in the Zeuglodon Valley further west.

In the well-marked hill distant 17 kilometres to the north-east of Gar el Gehannem, the soft fossiliferous sandstones of this series are crowded with Operculina, Nummulites, and many species of mollusca beautifully preserved.

At Gar el Gehannem the series is seen ([Fig. 2] and detailed section [page 36]) forming part of the slope of the hill, underlain by the Ravine beds, and capped by part of the Qasr el Sagha series. It here consists of yellow sandstones divided by a bed of clay; the sandstones are often crowded with nummulites (of two species); also Operculina (discoidea?), echinids, Balanus sp., Ostrea Reili, O. Fraasi, Carolia placunoides, and species of Pecten, Pinna, Cardita, Teredo, Turritella, and Cerithium.

Fig. 5.—Section of cliffs, western end of the Birket el Qurun.

Pleistocene.—(a) Lacustrine clays and sands with freshwater shells and fish-remains; Middle Eocene, 1. 14 Clays, sandstones and impure limestones; 15 White shaly clays and marly limestones.

In the Zeuglodon Valley, 12 kilometres W.S.W. of Gar el Gehannem, the brown sandstones of the Birket el Qurûn series are divided by a narrow band of fine-bedded grey clay. Most of the fantastically shaped hills on the south-west slope of the valley are carved out of the lower division of the sandstone. The concretionary beds of the Birket el-Qurûn series are not developed in this neighbourhood. Remains of Zeuglodon of both species (Z. Osiris and Z. Isis) are remarkably abundant and the skeletons of these cetaceans may be found in every stage of weathering. The larger species, Z. Isis, is the more common, and series of vertebrae, twelve to fifteen in number, can frequently be counted in situ. The remains are most abundant enclosed in the hard brown nodular bands of the series but in such cases it is almost impossible to extract specimens of any value. In one instance an almost complete skull of Z. Isis, measuring 116 cm. in length, was found enclosed in a large block of the nodular rock.[57] Bones are frequently to be observed protruding from the wind-worn sides of the small hills, while those portions of the skeleton already weathered out litter the ground below. Exposed they break up with rapidity, although where the enclosing rock is softer than the bone itself, parts of the skeleton beautifully preserved and perfectly free from matrix may sometimes be obtained.

The molluscan fauna is represented by very large numbers of pseudomorphs in sulphate of strontium (celestine) of the genera Lucina, Turritella, Fusus and Nautilus, the profusion of individuals of a species of the latter being very marked. In the case of lamellibranchs the radiating bundles of crystals of celestine are seen to originate from a point placed centrally on one of the valves, so that on this side (of a slightly weathered example) a radiating mass of crystals is seen, while on the other appear numerous contiguous circular areas, representing the terminal ends of the bundles of crystalline fibres or needles. Apart from the quantities of organic pseudomorphs, masses of crystalline celestine occur in the sandstones throughout the valley, and altogether the quantity of sulphate of strontium present must be very great. The gigantic oysters and other fossils which occur in some of the overlying higher beds, and the numerous individuals of nummulites in the sandstone itself, never seem to be replaced by celestine.

Nummulites of two species are very abundant in some bands and the presence in the Zeuglodon Valley of occasional individuals of the large N. gizehensis shows that in favourable localities this species persisted throughout the time represented by the deposition of the Ravine beds and ranged upward into the basal members of the Birket el Qurûn series.

In the higher hills within the valley, and in the hill-mass on the south side, the yellow sandstones of the Birket el Qurûn series pass up into the basal members of the Qasr el Sagha series. In their upper limits the sandstones become very nummulitic in places and at the top bands made up of Carolia and Ostrea occur. Above these, in the basal members of the Qasr el Sagha series, huge oysters and finely preserved specimens of Qerunia cornuta are conspicuous.

The dip in the valley is 2° north.

The southern face of the hill-mass lying immediately to the south of the Zeuglodon Valley is an almost sheer cliff of over 100 metres, descending to the silt covered basin below which has already been noticed ([page 23]). On this escarpment the hard nodular marly limestones of the Ravine beds are seen near the base, overlain by a mass of grey shaly gypseous beds; above, forming as a rule a vertical wall of rock, lies the hard massive brown sandstone of the Birket el Qurûn series, here undivided by clays; at the top, highly fossiliferous alternating clays and limestones are found forming the summit of the hills.

The exact junction between the Birket el Qurûn series and the overlying Qasr el Sagha beds is naturally perfectly arbitrary, many of the fossils being common to both groups. Carolia placunoides, which is perhaps the most abundant fossil in the Qasr el Sagha series, is sometimes very common in the upper beds of the underlying group, and, as shown before, is common enough in the still lower Nummulites gizehensis beds of Wadi Rayan. So that, though this fossil itself is no criterion, its relative abundance in the upper series justifies those beds being called the “Carolia beds,” the additional name of the Qasr el Sagha series being taken from the old ruin of that name where these beds are fully seen.

Plate VIII.

MIDDLE EOCENE ESCARPMENT (QASR EL SAGHA SERIES) 12 KILOM. WEST OF QASR EL SAGHA.

D.—Qasr el Sagha Series (Carolia Beds).

This division is strikingly developed in the north of the Fayûm, where it forms a bold escarpment of great length, consisting of an alternating series of very fossiliferous clays and limestones, with sands and sandstone in the upper beds, of a total thickness of 175 metres.

This series is the equivalent of the well known Upper Mokattam beds of Jebel Mokattam, immediately to the east of Cairo. The cliffs of this hill are among the best known in Egypt and have been studied by many geologists, including Zittel, Schweinfurth, Mayer-Eymar, etc.; these authors have classified the whole of the Upper Mokattam of Cairo as equivalent to the Upper Parisian (Middle Eocene) of Western Europe. The series is far better developed in the Fayûm than at Jebel Mokattam, where the total thickness is only some 70 to 80 metres.

In consequence of the discovery in these beds of a highly interesting vertebrate fauna, including land animals, the series becomes of the greatest importance. As already mentioned, as long ago as 1879, Schweinfurth, during a journey across the Fayûm, obtained remains of Zeuglodon in the underlying series from the island in the Birket el Qurûn. Subsequently [58] he obtained additional remains of the same cetacean in a violet marl belonging to the present series, from a locality 12½ kilometres west of Qasr el Sagha [59]; these remains, as already mentioned, were described by Dames as Z. Osiris. Since then important finds of land and marine mammals and reptiles have been made in different beds of this series; these will be referred to later.

The outcrop of the Qasr el Sagha series occupies a large part of the northern desert of the Fayûm. The beds are, however, best seen in the cliffs about 8 kilometres north of the Birket el Qurûn, where they form a steep double escarpment, running east and west, nearly parallel to the northern shore of the lake. The dip of the series being northward at a very low angle, and the upward slope of the ground being in the same direction, this cliff dies out a few kilometres north-east of Qasr el Sagha. A little further north, however, a N.W.-S.E. fold and fault again exposes nearly the whole of the beds of the series, forming prominent cliffs as before.

In the conspicuous hill 17½ kilometres 28° N. of E. (magnetic) of Tamia the series consists of innumerable alternations of clays and sandy limestone. The calcareous beds nearly always contain numerous examples of Carolia placunoides, Ostrea and Turritella of several species, but other well-preserved fossils are rare. The exposed beds here have a thickness of about 55 metres, and are underlain by the Birket el Qurûn beds with a well-marked band of concretionary sandstone, the thickness of the two series together being 127 metres. The upper beds of the former series are not here exposed, the top of the hill being formed of well-rounded flint and quartz pebbles embedded in a base of finely crystalline gypsum (2 metres thick), a deposit of Pleistocene times.

To the north of Tamia a large area of desert is occupied by the beds of this series; the district has the character of an undulating plain with occasional groups of hills and low irregular escarpments. At the groups of hills 12 kilometres N.N.E. of Tamia, and just to the east of Garat el Faras, the Qasr el Sagha beds are found to consist as usual of an alternating series of sands, sandstones, clays, marls and limestones, with numerous individuals of Ostrea, Carolia and Turritella, besides vertebræ, teeth and spines of large fish.

We may pass now to the locality where this series shows its best development and exposure, the beds being all concentrated in one bold escarpment, generally divisible into an upper and a lower cliff. These cliffs overlook the Birket el Qurûn, although distant usually about 8 kilometres, being separated from the lower escarpment of the Birket el Qurûn series (immediately above the lake shore) by a broad plain, the surface of which is usually the dip-slope of a hard bed of sandstone. From Qasr el Sagha (6½ kilometres N.N.E. of Dimê) these cliffs trend westward, keeping approximately the same distance from the north shore of the lake; they have been followed and mapped for a distance of 70 kilometres to a point 13 kilometres N.N.W. of Gar el Gehannem, whence they could be seen still trending in a direction slightly south of west (see [Plate XVII]).

Small faults are of frequent occurrence along these escarpments, but are not of other than local interest; they almost invariably have their downthrow to the north, and it seldom exceeds a few metres. [Fig. 5] shows a section through one of these faults near Qasr el Sagha.

The following detailed section ([Plate XXIII]) will show the character of the beds forming this division. As might be expected in such a series, although the calcareous bands are fairly constant, there is a continuous change of character among the sandy and clayey sediments from point to point; the false-bedding is in places very striking.

The main part of the section was measured 3½ kilometres north-east of Qasr el Sagha, but the lower beds not being exposed at that point, they were added from the cliffs at the ruin itself. The total thickness is 154 metres.

Top.		Thickness in metres.
1.	Hard, white, grey-weathering, sandylimestone with numerous shell-casts: Echinolampas Crameri,Loriol, Plicatula Bellardi, May.-Eym.	2
2.	False-bedded sand and sand-rock with greyand green clays; concretions and bands of ironstone.
	Hard, dark-brown or purplish ferruginoussandstone band. Occasional vertebrae of Zeuglodon Osiris,Dames, Pterosphenus (Mœriophis) Schweinfurthi,Andr., crocodilian and fish-remains; coprolites	16
3.	Hard, calcareous, ferruginous, clayeysandstone with brown ironstone concretions. Occasionalfish-spines.
	Clays with massive veins of gypsumforming a stock-work, and left weathered out above surface.Cardium Schweinfurthi, May.-Eym., Cardita fajumensis,Oppenh., (Cossmannella ægyptiaca, May.-Eym [60]), Crassatellithes sp.	9
4.	Hard, yellow, gypseous sandy limestone orcalcareous sandstone	1½
5.	Sandy, glauconitic clays with gypsum;oyster-bed at base in places. Alectryonia Clot-Beyi,Bellardi, Exogyra Fraasi, May.-Eym.	10
2nd escarpment.
6.	Hard or friable limestone, sometimessandy, full of Carolia placunoides, Cantr., and ExogyraFraasi, also Ostrea aff. heteroclyta, Defr.,Ostrea Reili, Fraas., O. elegans, Desh., PlicatulaBellardi, May.-Eym., Pectunculus (?) ægyptiacus,Oppenh., Qerunia (Hydractinia) cornuta,May.-Eym.	2
7.	Purplish clays interbedded and remarkablycurrent-bedded with ash-grey sands, with both ferruginous andhighly carbonaceous bands with plant-remains, lignite and naturalcharcoal. Vertebrate remains fairly common, the mammalian includingZeuglodon Osiris, Eosiren libyca, Andr.,Mœritherium Lyonsi, Barytherium? Andr.; the reptilianStereogenys Cromeri, Andr., and Tomistoma africanum,Andr., with numerous coprolites; also frequent remains of siluroidand other fish. Masses of coral, Astrohelia similis, Felix,in places	12
8.	Hard grey, close-grained, concretionarysandstone, frequently weathering into huge elongated roundedmasses; Turritella pharaonica, Cossm.
	Hard, purplish clays with grey sandyclays, sandrock, etc. Occasional crocodile and fish-remains	4
9.	Hard ripple-marked sandstone.False-bedded sandstones with clay partings; ferruginous andlignitic bands with lumps of lignite. Occasionally coprolites andremains of Sirenia and Crocodilia are numerous	7
10.	Hard or friable brown sandy limestonewith shell-casts filled with scalenohedra of calcite. Caroliaplacunoides, Turritella sp.	½
11.	Gypseous clays, with red ferruginousband; weathering to paper-shales below	4½
12.	Light-yellow limestone and calcareoussandstone with sharks’ teeth, Mesalia fasciata, Lam.,Cassidaria sp., Rimella rimosa, Sol.,Trachelochetus bituberculatus, Cossm., Turritellacarinifera, Desh., T. Lessepsi, May.-Eym., Carditafajumensis, Oppenh. Goniopora?	1
13.	Slate-blue and brown gypseous clays withband containing Mesalia sp., Cassidaria nilotica,Bell., Exogyra Fraasi and Goniaræa elegans	3
14.	Sandstone and sandrock, light yellow	1
15.	Yellow sandy friable limestone with castsof shells and Mesalia fasciata, M. oxycrepis,May.-Eym., Turritella Lessepsi, T. pharaonica,Cossm., Alectryonia Clot-Beyi, Ostrea Reili	½
16-17.	Sands, sandy clays and clays with adouble band of limestone containing Ampullina hybrida, Lam.,Melongena nilotica, var. bicarinata, May.-Eym.,Tudicla aff. umbilicaris, May.-Eym., TurritellaLessepsi, T. parisiana, May.-Eym., Solarium sp.,Alectryonia Clot-Beyi, Plicatula polymorpha(occasional), Lucina fortisiana, Defr., L. pharaonis,Bell., Mytilus affinis? J. and C. Sowerby, Astroheliasimilis, Goniaræa elegans, Mich.; numerous vertebrateremains both above and between limestones including ZeuglodonOsiris, Eosiren libyca, Barytherium grave, Andr.,Moeritherium Lyonsi, M. gracile, Andr.,Gigantophis Garstini, Andr., PterosphenusSchweinfurthi and Tomistoma africanum, Andr. The remainsof a siluroid fish are abundant; also PropristisSchweinfurthi, Dames. Large numbers of coprolites. Silicifiedwood	12
18.	Brown sandy limestone with casts ofshells, Akera aff. striatella, Lam.,Ampullaria, n. sp., Gisortia gigantea, Munst.,Lanistes antiquus, Blanck., Melongena nilotica, var.bicarinata, Mesalia sp., Cassidaria nilotica,C. aff. nodosa, Solarium aff.bistriatum, Desh., Alectryonia Clot-Beyi, CardiumSchweinfurthi, Exogyra Fraasi, Lucina pharaonis,Bell., Macrosolen Hollowaysi, J. Sowerby, Meretrixnitidula, Lam., M. parisiensis, Desh., Ostreaflabellula, Lam., Tellina sp., overlying clays withgypsum	4
19.	Sandy limestone with numerous Caroliaplacunoides and Turritella imbricataria, Lam.	1
20.	Greyish-blue and brown ferruginous,sandy, and other clays. Plant remains	13
21.	Friable shelly limestone with occasionalsmall calcite veins	½
22.	Clays	4
23.	Hard yellow sandy limestone withOstrea and Anisaster (Agassizia)gibberulus	½
24.	Clays with thin bands of fibrousgypsum	6
25.	Hard friable shelly limestone withnumerous fossils, including Dictyopleurus Haimi, Dunc. andSlad.; Akera aff. striatella, Turritellacarinifera, T. imbricataria, T. pharaonica,Alectryonia Clot-Beyi, Arca tethyis, Oppenh.,Cardita aff. carinata, J. Sowerby, C. aff.depressa, Locard., C. aff. triparticostata,Cossm., C. cf. gracilis and depressa, Locard.,Cardita fajumensis, Cucullæa aff. crassatina,Lam., Exogyra Fraasi, Glycimeris (Pectunculus)pulvinatus, Lam., Ostrea aff. Reili,Spondylus ægyptiacus, Bull. Newt., Pecten solariolum,May.-Eym., P. moelehensis, May.-Eym., Qeruniacornuta, Euspatangus cairensis, Loriol, Linthiasp., Anisaster gibberulus, Schizaster aff.africanus, Loriol; bryozoa	½
26.	Sandy clays with gypsum	7
27.	Friable, gypseous, impure limestone withExogyra Fraasi, Carolia placunoides,Turritella sp., Qerunia cornuta, AlectryoniaClot-Beyi	½
28.	Sandy gypseous clays	3
29.	Friable sandy limestone with Caroliaplacunoides, Exogyra Fraasi, Turritella sp. (Theruin of Qasr el Sagha is built on this bed)	1
30.	Gypseous sandy clays with occasionaloyster-limestone with Qerunia cornuta; ferruginous sandstoneband, etc.	27
	Total	154
Hard grey sandstone withZeuglodon and numerous Carolia, Ostrea, etc.,in places, capping plain to south of Qasr el Sagha and forming thetop of the “Birket el Qurun series.”

The chief divisions of the series remain fairly constant and can be recognized and followed for many kilometres westwards.[61] The lower beds form the summits of Gar el Gehannem and the neighbouring hills (see [Fig. 2] and section [p. 36]), the upper beds of the series being exposed in the higher escarpments to the north.

Although vertebrate remains are more common on some horizons [62] than on others, they are occasionally met with in most of the beds. The most prolific bone horizon is, however, about half-way down, i.e., those beds numbered 16 and 17 in the above section; bed 7 also yielded a number of remains. At the point where the upper part of the section was measured, 3½ kilometres north-east of Qasr el Sagha, the beds 16 and 17 yielded a considerable number of land-animal remains, all of which occurred within a fairly confined space, suggesting that they had been carried out from the land to this point by a strong river-current and deposited when the latter became too feeble to carry them further out to sea. The same beds were also examined in the faulted bay 8 kilometres to the north, but no bones, or at most a very occasional fragment or two, were obtained here. This is easily explained by the greater distance of this locality from the land-mass to the south. Westwards the same beds were always found more or less bone-bearing, isolated detached mandibles, limb-bones and vertebræ of Mœritherium, being of frequent occurrence, although no such complete remains were found as those from near Qasr el Sagha. Reptilian and fish bones are very widespread throughout the area. An extensive and detailed examination of these beds over a large area can hardly fail to yield important results, as other localities where skeleton-carrying currents came out from the land would very likely be discovered.

That the Qasr el Sagha series was deposited in fairly shallow water at no great distance from land seems certain, not only from the general lithological character of the beds but from the number of land-animal remains and the frequency of river and shore-frequenting whales, dugongs, crocodiles and turtles. The clays, moreover, are found to abound with impressions of plants, and in some cases are highly lignitic, being made up of compressed masses of vegetation including solid twigs, now found in a state more resembling charcoal than ordinary dense lignites; some bands approximate to an impure brown coal. In certain beds of the series further to the west, very thin seams of true coal occur; they were, however, never seen to exceed one or two millimetres. The intercalated bands of limestone are generally impure and do not indicate any great conditions of depth, but only rather a temporary cessation in the supply of sand and clay. Corals, moreover, abound along many horizons.

Plate IX.

UPPER BEDS OF FLUVIO-MARINE SERIES WITH BASALT CAP, LOOKING WEST FROM THE EASTERN EXTREMITY OF JEBEL EL QATRANI.