On the north, east, and south-east sides of the Fayûm, well marked terraces of gravel are found at certain levels up to a maximum of about 170-180 metres above sea-level. Nine kilometres east of Sêla the summit of the ridge separating the Fayûm and the Nile Valley is formed of thick deposits of gravel, laid irregularly and unconformably on the top of limestones belonging to the Birket el Qurûn series. The lowest terrace occurs only 15 metres above the canal[86] running along the outside of the cultivation. The main deposit of gravel is laid on the top of the limestones and marls at 70 metres above the canal; it is some 50 metres thick (summit 120 metres above canal) and consists of a mass of well-rolled flint and quartz pebbles, with blocks of limestone (frequently full of well-known Eocene fossils such as _Carolia placunoides_). Large well rounded blocks of grey quartzite and pebbles of black quartzite also occur, besides rounded blocks of silicified wood. A certain amount of false-bedding occurs and false-bedded sand was noticed in places. Numerous derived rolled fossils are present, but no contemporaneous remains were found. On the summit of the ridge is situated the remnant of an old pyramid-like building. Fig. 8 shows the relation of these gravels to the underlying rocks. [Illustration: FIG. 8.—_Sketch showing relations of Middle Eocene to Pliocene Gravel Terraces on the east side of the Fayûm._ _Birket el Qurun series._—(_a_) Clays, marls and limestone; (_b_) Limestones with _Operculina_ (_O. discoidea?_). Pliocene (to Pleistocene); (_c_) Coarse deposits of gravel, etc., with huge blocks of derived Eocene limestone with _Carolia_, etc.; (_d_) sands and sandrock with leaves of hard sandstone; (_e_) sand, gravel and conglomerate.] At the spur of the cliff immediately to the east the terrace is laid on to limestones of the Birket el Qurûn series at a height of 32 metres above the canal. Enormous blocks of _Carolia_-limestone, some exceeding 3 × 2 × 1·5 metres in measurement, are included in this deposit; such blocks cannot have been transported far, and were doubtless derived from formerly-existing higher beds in the immediate neighbourhood. The matrix of the deposit is usually crushed limestone with sand and gravel. Occasional fragments of silicified wood (and further west large logs), evidently derived from the Fluvio-marine beds, also occur. In favoured localities the relation of the gravels to the Eocene is still better seen; the lower beds of the terrace here are sometimes formed of sands and sandy beds dipping 10° eastward. At the little promontory 9 kilometres east of Sersena the same deposits reach an altitude of 157 metres above the canal below.