The Topography and Geology of the Fayum Province of Egypt

Section Iv.—Wadi Rayan and Neighbourhood—

Colonel Western’s survey. Sir William Willcocks’ report. Borings. Details of proposed reservoir. Schweinfurth’s estimate of salt content. Willcocks’ “Assuan Reservoir and Lake Moeris.” Detailed geological examination not yet undertaken. Traverse from Nile Valley through Wadi Muêla and Rayan to Gharaq. Warshat el Melh and springs of Wadi Muêla. Der el Galamûn. Pass from Muêla to Rayan. Sand accumulations. Wadi Korif. Springs of Wadi Rayan. Analyses and output of water. Geological succession in Wadi Rayan. General geology of floor and bounding walls. Ridge separating Rayan and Gharaq. Apparent absence of Nile deposit and freshwater shells in Wadi Rayan. Question of leakage through ridge. Permeability of Rayan if used as a reservoir. Salinity of water 16

Section V.—Central Area of the Region—

Area and features. Dip-slope of surface. Drainage basins of central plain. Pools formed by rainfall. Tamarisk growth. The eastern area covered by alluvium. The bounding plateau to the north. Ghart el Khanashat dunes 24

Section Vi.—the Ridge Separating the Nile Valley and Fayum—

Width and highest points. Strata forming ridge. Gravel terraces. Low points of ridge. Original access of Nile waters to depression. Formation of lake and deposition of sediment in Fayûm 25

Section Vii.—the Northern Desert Region—

Escarpments and plateaux. Extreme west and south-west limits of area. Ferruginous silicified puddingstone of ancient rivers. Jebel el Qatrani. Widan el Faras. Elwat Hialla. Garat el Gindi. Garat el Faras 26

Part Ii.—Tectonics.

SECTION VIII.—FAULTING AND FOLDING—

Origin of depression. Evidence in drainage ravines El Bats and El Wadi. Deep boring at Medinet el Fayûm. Dr. Blanckenhorn’s theory that depression owes its origin to extensive fault system. Fault theory disproved. Fault N.N.E. of Qasr el Sagha. Numerous local strike faults of small throw. Occasional influence of fractures in determining escarpments 29

Part Iii.—Geology.

SECTION IX.—GENERAL AND CLASSIFICATION OF STRATA—

Depression cut out in sedimentary rocks. Local lava flows. Dip. Oldest beds the Nummulites gizehensis limestones of Middle Eocene. Fluviomarine series of Upper Eocene and Oligocene age. Absence of Miocene strata. Pliocene, Pleistocene and Recent. Table showing succession and classification of strata 33

Section X.—Middle Eocene—

A.—Wadi Rayan Series.—Work of Schweinfurth and Mayer-Eymar. Section at entrance to Wadi Muêla on Nile Valley side. Strata of cliffs near Der el Galamûn. Detailed section measured at Jebel Rayan. Mayer Eymar’s section in Wadi Muêla 35

B.—Ravine Beds.—In ravines of El Bats and El Wadi. Relation to underlying series seen at Gar el Gehannem. Section at Gar el Gehannem. Fauna of strata. In ravines unconformably overlain by Pleistocene, etc. Form plain bordering cultivation on east side. Extension into Nile Valley. Occurrence at Sersena and Tamia. Forming base of Geziret el Qorn and lower part of northern escarpment of Birket el Qurûn. West end of lake. Hard siliceous bands give rise to horns or promontories of lake. Ravine Beds in the Medinet el Fayûm boring. Thickness 37

C.—Birket el Qurun Series.—Homotaxial with quarried limestones of Cairo. Foraminiferal beds. Extension of series. Section at Ezba Qalamsha. Section north of Lahûn pyramid. East of Sersena and north-east of Rubiyat. Section 17 kilometres 28° N. of E. of Tamia. Series characterized by large globular concretions. Development and fauna in Geziret el Qorn. Zeuglodon remains. Profile at Geziret el Qorn. Rich molluscan fauna. Section on mainland opposite Geziret el Qorn. Section at west end of Birket el Qurûn. Formation of earth-pillars. Extension west of the lake. Development of the series in the Zeuglodon Valley. Abundance of skeletons of whales. Molluscan fauna. Pseudomorphs in celestine. Hill mass south of the Zeuglodon Valley. Junction of Birket el Qurûn series with overlying stage 41

D.—Qasr el Sagha Series.—Equivalent of the Upper Mokattam of Cairo. Greater development in Fayûm. Vertebrate fauna of series. Schweinfurth’s original discovery of cetacean remains. Recent discovery of land and marine mammals. Extension of series generally. N.N.E. of Tamia. At Garat el Faras. In the cliffs north of the Birket el Qurûn. Detailed section near ruin of Qasr el Sagha. At Gar el Gehannem and westwards. Land animals floated out from land by river currents. The series a littoral deposit. Lignitic beds and thin seams of coal 49

Section Xi.—Upper Eocene — Lower Oligocene—

E.—Fluvio-marine Series.—Nature of sediments, Interbedded basalts in upper part. Character of its invertebrate fauna. Conditions of deposition of series. Continuance of similar conditions to Miocene and even Pliocene times. Bone-beds at base of series. Association of skeletons of animals and forest trees. Preservation of remains. Analysis of fossil bones. Relation of Fluvio-marine series to underlying stage. Characteristics of the group. Its development in the field. Its slight development at Elwat Hialla. Section near Elwat Hialla. Constant northerly dip. Organic (molluscan) remains 9 and 14 kilometres north of Qasr el Sagha. Detailed section from near Qasr el Sagha to Widan el Faras. Determinations of mollusca from the series. Tripartite character of the series west of Widan el Faras and Qasr el Sagha. Occurrence of calcite, gypsum and chalcedony. Tabular chert and flint. Ancient workings. Extent of basalt. Silicified trees 53

F.—Age of the Fluvio-Marine Series.—Difficulty in the determination of age owing to paucity of fossils. Zittel’s tabulation of “Schichten von Birket el Qurûn” as Oligocene. Mayer-Eymar’s age determinations. Schweinfurth’s comparison of the series with the Scutella beds of Der el Beda near Cairo. Blanckenhorn’s determinations. The stratigraphical position of the series and relationship to Qasr el Sagha series. Stratigraphically lower than the Lower Miocene of Mogara. Whole complex in all probability of Upper Eocene and Oligocene age, the transition being at or near the basalt sheets 63

G.—The Position of the Land Mass from which the Mammals were derived.—Proximity of continental land. Absence of branches on fossil trees. Massif of Abu Roash perhaps an island to the north. Extension of Eocene sea. Continual retreat of the sea northwards. Rivers emerging from the land. Number and positions of such rivers doubtful. Evidence for river passing from the modern oasis of Baharia through Gar el Hamra to the Fayûm. Lacustrine and fluviatile deposits along the course. Huxley’s theory of immigration and invasion of animals into Africa. Fayûm animals belong to an extinct African fauna of Tertiary times. Contains the earliest and most primitive forms of elephants and other groups. Emigration and immigration. Prof. Osborn’s theory of the African continent as a centre of radiation. Confirmation by the Fayûm mammal discoveries. List of new species obtained from the Fayûm 65

H.—The Absence of Miocene deposits in the Fayûm.—The Fayûm a land area in Miocene times. Miocene deposits of Mogara. Lithological similarity. Probable persistence of geographical conditions 71

Section Xii.—Pliocene—

J.—Marine deposits: Middle Pliocene.—Marine deposits of Sidmant with typical Middle Pliocene mollusca. Relation of these deposits to the gravel terraces as yet unknown though important 71

K.—Borings on Rock Surfaces; of doubtful age.—Apparently due to marine boring mollusca. No exact evidence as to age. (α) Low level borings from zero to 20 metres above sea-level. (β) High level borings at 112 metres above sea-level. Limited occurrences of borings 71

L.—Gravel Terraces:? Upper Pliocene.—Well marked terraces of gravel up to 170-180 metres above sea-level. East of Sêla. Character of deposit. East of Sersena and Roda. N.N.E. of Tamia, N.N.E. of Garat el Faras, east and north-east of Garat el Gindi. Relation to different series. Character of gravels at Elwat Hialla. West of Elwat Hialla gravel terraces almost completely removed by denudation. Traces near Widan el Faras and near Garat el Esh. Height of terraces in latter locality determined as 170 metres above sea-level. Terrace marks shore line of great sheet of water, whether freshwater or marine. The great plains of the Fayûm possibly in part plains of marine denudation 73

M.—Gypseous Deposits: probably dating from the close of the Pliocene.—Extension in Nile Valley and Fayûm. Section at Medum. On the east side of the Fayûm. Gypsum cemented conglomerate. Close connection with upper part of gravel terraces 77

N.—Summary of Pliocene Period 78

Section Xiii.—Pleistocene—

Earliest existence of a freshwater lake. Probably not a remnant of the Pliocene sea or lake in which gravel terraces were formed. Intermediate denudation of area. Date of earliest entry of Nile waters doubtful. Freshwater lake of Nile Valley. Drainage down the Nile Valley and establishment of river. Breaking down of gravel ridge separating the valley and the Fayûm. Entrance of flood waters. Formation of lake and deposition of sediment. Subsequent disconnection of Nile Valley and Fayûm owing to erosion of river bed. Rise of Nile in prehistoric and historic times. Reconnection. Geological evidence for the existence of great freshwater Pleistocene lake. Position and dimensions. Fossil fauna of the lake, and its difference from all other Egyptian faunas. Blanckenhorn’s conclusions 79

Section Xiv.—Recent 81

O.—Prehistoric.—Abundance of worked flints. Shores of lake inhabited by Neolithic and probably prehistoric man. Tamarisk remains. Probable age of flints anterior to Egyptian historic period 82

P.—Historic.—Relations of the Nile Valley river system and the Fayûm. Lake Moeris a regulator of the Nile floods. Brought under control in XIIth dynasty. Early references to Lake Moeris. Its position disputed in modern times. Linant de Bellefonds’ assertion disproved by Sir Hanbury Brown. Archæological evidence for the site. Present day fauna of the Birket el Qurûn. Modern deposits. Blown sand. Erosion 82

APPENDICES 87

1. Previous literature relating to the Fayûm 87

2. Fayûm lamellibranchs mentioned in Oppenheim’s “Zur Kenntnis alttertiärer Faunen in Ægypten.” 89

INDEX 91

LIST OF ILLUSTRATIONS.

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