The Melania occurring in mass in the uppermost calcareous bed appears to be a new species[73] whose nearest relation must in any case be M. Nysti of the Oligocene, not M. muricata of the Eocene, amongst forms at present known.
Turritella angulata, Sow. A marine form, occurring below the basalt and indubitably this species, as it is well preserved and easily determined[74]; T. angulata ranges from the Middle Eocene to the Lower Oligocene of the East and occurs in the Upper Mokattam of Syria.”
From Widan el Faras the series continues westwards, forming several escarpments, the uppermost that of Jebel el Qatrani, and maintaining the same general characters. The tripartite character of the series, already noticeable between Qasr el Sagha and Widan el Faras (see foregoing section) becomes still more marked. The lowest division is very largely composed of fluviatile sands and sandstones, frequently coarse-grained and usually markedly current-bedded, divided by clays and containing an abundance of silicified trees and quantities of vertebrate remains. These soft beds, some 60 metres in thickness, have as a rule an extensive outcrop, forming an undulating plain averaging two or three kilometres in width. They are overlaid by some 17 metres of harder dark red sandstones, which invariably form a well-marked escarpment capped by a very constant two or three metres band of hard white or pinkish calcareous grit. This grit varies in composition, frequently passing into a marl; and one of the characteristics of this and the underlying red beds is the abundance of nodular masses of calcite and gypsum. In some localities, as for instance 3 kilometres W.N.W. of Qasr el Sagha, numerous spherical nodules of beekitic chalcedony occur in the beds of this division, and some of these when broken are found to be geodes lined with beautiful crystals of quartz and calcite.
The next division consists of some 60 metres of alternating sandstones and clays with occasional thin calcareous bands in the upper part, and capped by a well-marked hard cherty limestone, frequently passing into a dense tabular chert or flint. This exceptionally hard band generally forms a dip-slope plain of some width, before the softer basal members of the third and highest division overlie it. The siliceous bed caps many of the most notable hills in the district; among others may be mentioned the big isolated hill 9 kilometres north-west of Garat el Esh, and the hills five kilometres N.N.E. of the same point. This is the only horizon throughout the Eocene succession of the Fayûm on which an abundance of flint is met with; that it was well known and exploited in early times is evident from the old pits met with on the summits of the hills overlooking the main bone-pits, a few kilometres north of Garat el Esh. As no worked flints were noticed round the workings it is probable that the material was excavated and carried away to the borders of the lake, there to be fashioned into the harpoons, saws and other implements which are so commonly found scattered at the present day near the margin of the old lake site.
The uppermost division of the Fluvio-marine series consists of over 100 metres of variegated sediments and forms the escarpment of Jebel el Qatrani itself, capped by the conspicuous band of hard black basalt, which is itself overlain by a further 20 metres of similar sediments. The basalt has a thickness of over 20 metres in places, though its average is considerably less; at the base it is frequently decomposed, soft, and of a brown colour.
At a point due north of the western end of the Birket el Qurûn the interbedded basalt sheet terminates, and no further flows were seen as far as the point up to which the series was mapped, nearly due north of Gar el Gehannem. As far as could be seen on a traverse through the Zeuglodon Valley to the south-western limits of the depression no further basalt flows occur.
Section from the base of the Fluvio-marine series, 2 kilometres north of Garat el Esh, to the summit of Jebel el Qatrani 5½ kilometres north of the bone-pits. (See Plates [XVIII] and [XXIV]).
| Summit of plateau. | Approximate thickness in metres | ||
|---|---|---|---|
| 1. | Coarse sandstones and grits | 13 | |
| 2. | Basalt | 25 | |
| 3. | Yellow sands and sandstones, capped by 3m. of hard concretionary grey sandstone with occasional mammalianbones (underlying basalt in scarp and capping outlying hill) | 15 | |
| 4. | Hard sandstones with clayey bands | 8 | |
| 5. | Sandy and clayey beds | 5 | |
| 6. | Hard yellow calcareous grit | 5 | |
| 7. | Clays and clayey marls | 7 | |
| 8. | Sandy beds | 15 | |
| 9. | Hard sandstone (forms connecting ridgebetween hill and escarpment) | ½ | |
| 10. | Clays with thin sandstone bands | 40 | |
| 11. | Variable sandy and marly red clays with ahard yellowish sandstone band ten metres from base | ||
| Base of isolatedhill. | |||
| 12. | Soft sands with chelonian and crocodilianremains | 4 | |
| 13. | Sandy clays with chelonian and mammalian(Arsinoitherium) bones, capped by coarse grit, in partferruginous silicified grit and quartzite | 1 | |
| 14. | White calcareous grit and marlylimestone. Band of flint in places | ||
| Summit of hilloverlooking bone-pits. | |||
| 14. | Sandstone, becoming calcareous andpassing up into 3 m. of hard white calcareous grit, and yellowishwhite bedded marly limestone with calcite druses. Capped by ¼ m.hard tabular chert and flint | 10 | |
| 15. | Finely laminated grey shaly clays, sandyand marly clays, capped by 2 m. of mottled yellow and red sandstoneand sandstone-grit | 10 | |
| 16. | Hard red, green, and brown sandstone | ||
| 17. | Variegated grey, green and red clays,marly clays and sandy beds, with thin bands of sandstone. Morearenaceous towards top | 21 | |
| 18. | Hard grey sandstone; greenish sandyclays; hard dark red marls and marly clays at top | 6 | |
| 19. | Thin band of hard yellow limestone,capping salty red clays and sandy clays | 6 | |
| 20. | Soft greenish clayey sandstone capped by½ m. of hard false-bedded concretionary sandstone with numerousenclosed coprolites | 3 | |
| Base of hilloverlooking bone-pits. | |||
| 21. | Pink calcareous grit (forming summit oflowest escarpment), with small flint and quartz pebbles in somelayers. An abundance of calcite and gypsum | 3 | |
| 22. | Mottled red and green clayey sandstone,clays and clayey marls. Passing up into a hard sandy (or clayey)dark red marl with greenish mottlings | 7 | |
| 23. | Light yellow finely-laminated sandrockpassing up into dark red sandrock. Some clayey bands | 10 | |
| 24. | Coarse unconsolidated false-bedded sands,with occasional bands of clay and consolidated sandstone bands.Numerous silicified trees and abundant mammalian and reptilianremains. (See list in Bed 49 of Widan el Faras [section]). Bone-pits are in this bed | 40 | |
| 25. | Thin band (½ m.) of hard sandstone withsometimes impure calcareous grit | 10 | |
| 26. | Hard light yellow sandstone, often verycoarse, and with red bands | ||
| 27. | Soft brick red and light yellow sands andsandstones, (seen on plain and overlying uppermost limestone of theMiddle Eocene) | 20 | |
| Base ofFluvio-marine Series. | |||
Plate XI.
