The topography and geology of the Fayum province of Egypt

by H. J. L. Beadnell

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
				(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.]