The following section was measured on the mainland[54] opposite the island Geziret el Qorn. _Top._ Metres. 1. Gypseous clays, separated by a band of brown sandstone crowded with white well-preserved shells, including numerous individuals of _Plicatula polymorpha_, _Ostrea_, _Turritella_ and _Lucina pharaonis_. Large vertebrae of _Zeuglodon Isis_ occur on this horizon further to the north-east 8 2. Sandstones and gypseous clays. Although here the sandstones are not hard or predominant, this bed is equivalent to the hard sandstone full of borings capping the plain between the ruins of Dimê and the top of the escarpment overlooking the lake. Further north this bed often contains numerous _Carolia placunoides_ and _Ostrea_ 3 3. Gypseous clays 3 4. Clays, brown sandstones, and occasional beds of limestone, often very fossiliferous, containing _Ostrea Reili_, _Carolia placunoides_, _Cardita Viquesneli_, d’Arch., _Lucina_ sp., _Turritella pharaonica_,[55] _Clavelithes longævus_, _Qerunia cornuta_, etc., etc. 10 5. Clays with fossils as in last bed, capped by hard band of shelly sandstone 3 6. Alternating yellow-brown sandstones and gypseous clays 10 -- Total thickness 37 -- Bed with weathered-out sandstone concretions at top—upper bed of section at Geziret el Qorn.[56] At the western end of the Birket el Qurûn the series is well marked, the sandstone beds forming the steep face of the bold precipitous cliffs which are so marked a feature at this end of the lake. The group has a thickness of some 50 metres and is overlain by the lower beds of the Qasr el Sagha series; it is more convenient here to give the entire section of the cliffs down to the base of the series under discussion:— _Top of Cliffs._ Metres.