Above the Qasr el Sagha series, and well marked off from them both lithologically and palæontologically, is found a great thickness of variegated sands, sandstones, clays and marls, the “Fluvio-marine Series” (Jebel el Qatrani beds), divided near the summit by one or more thick intercalated lava sheets, the latter forming a convenient junction line. This series of variegated beds is of Upper Eocene—Lower Oligocene age. No Miocene strata have been recognized within the area, but further north, as at Mogara, Lower Miocene deposits occur;[34] and it is probable that there is a continuous series of lithologically similar beds from the summit of the Fayûm escarpments (Lower Oligocene) to the Mogara Miocene. The Pliocene is probably represented by the great terraces of gravel—raised beaches—which are such a marked feature in the geology of the district. Fossiliferous Pliocene deposits have also been recorded from the south part of the area by Schweinfurth.[35] Pleistocene and Recent are abundantly represented by lacustrine clays, both ancient and modern, alluvial land and blown sand, the formation of which deposits is continuing at the present time. The following table will show the sequence of strata and the classification adopted in the present memoir:— TABLE SHOWING SUCCESSION AND CLASSIFICATION OF STRATA IN THE FAYUM. -----------+---------+--------+-----------+--------------------------- | | |Approximate| | | | average | | | | thickness | | | | in metres,| | | | north part| | | | of Fayum. | | | +-----------| | | | | Alluvial soil, clays, | | | | sands, etc. RECENT | | | | AND | | | | Blown sand. PLEISTOCENE| | | | | | | | Lacustrine clays, | | | | extending to about 23 | | | | metres above sea-level. -----------+---------+--------+-----------+--------------------------- | | | | Gravel Terraces (? | | | | Pleistocene). | | | | (MIDDLE?) | | | | Shell-borings on rock PLIOCENE | | | | surfaces. | | | | | | | 50 | Fossiliferous deposits of | | | | Sidmant. -----------+---------+--------+-----------+--------------------------- | | | |_Fluvio-marine Series | | | |(Jebel el Qatrani beds)_.