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