White marly limestone with much salt } probable { and fish-remains (fish-scales, etc.) } part of { 2 } Ravine beds. { Yellow sandstone with fish-scales, etc. } { 3 The gravel deposits along the east side of the Fayûm are always capped by a gypseous bed. The latter is often 2 metres thick and frequently occurs as solid and almost pure white crystalline gypsum; sometimes it is calcareous and is frequently deposited in a tufaceous manner, especially resembling a tufa on the weathered surface. At other times it passes into a yellowish compact mass and may be very saliferous. Frequently the deposit is full of rounded pebbles, the latter being often in the greater proportion and forming a sort of gypsum-cemented conglomerate. Not unfrequently it is impossible to draw any divisional line between the terrace gravels and the gypseous gravels above. Probably they are both closely connected and of Upper Pliocene age. _N._—=Summary of the Pliocene Period.= From the above descriptions it is probable that the Pliocene period is represented in the Fayûm by the following:— (1) Marine beds of Sidmant, undoubtedly of Middle Pliocene age and reaching a level of from 60 to 70 metres above present sea-level. (2) Borings on exposed rock-surfaces at two distinct levels, the lower 0-20 metres, the higher some 112 metres, above sea-level. These borings appear to be the work of marine boring mollusca, and although those on the lower level may perhaps be of Middle Pliocene age with the Sidmant beds, the similar examples discovered at a much higher altitude (112 metres), point to the sea having attained a much higher level in later, perhaps Upper Pliocene, times. (3) An extensive beach or terrace of gravel on the south-east, east, and north sides of the Fayûm, attaining a maximum level of about 170 to 180 metres above sea-level. All the known facts seem to be satisfied if we imagine that in the Middle Pliocene the sea occupied the area, depression probably continuing until the 112 metre level with the highest borings was reached. Perhaps the lowest part of the terraces was formed during this time. In the later Pliocene times we may infer that the area was occupied, up to 180 metres above present sea-level, by a vast inland lake, perhaps of brackish water, connected with the sea on the one hand and the fiord or lakes of the Nile Valley on the other, the deposits of which have been described elsewhere[88]. Along the margins of this gigantic lake, these great accumulations of gravel might well have been formed, chiefly of material derived from the immediate shores, augmented perhaps by a certain amount of sediment brought by river-currents from the south.