More extended examination of the Fayûm region supports my original conclusion[26] that the depression owes its origin to the same causes as have given rise to the other oases-depressions of the Libyan Desert, namely Baharia, Farafra, Dakhla and Kharga[27]. No evidence has as yet been met with which would suggest that earth-movements have played any important part in the formation of the Fayûm depression. Local faults, for the most part of short length and slight throw, occur at certain points, but the influence of these is strictly limited to their immediate neighbourhood. In fact, an examination of the desert margin of the Fayûm conclusively proves that the depression has been cut out through the action of ordinary subaerial denuding agents. The somewhat prevalent idea that the central portion of the depression, that covered by alluvial soil and the water of the lake, is faulted down, also rests on no foundation, all available evidence pointing in an opposite direction. Throughout the margin of the alluvial covered area the Eocene beds forming the surface of the desert can be observed to pass regularly under the cultivated lands; moreover, the same strata are frequently exposed in the bottoms of canals, drains, etc., far within the cultivation. The big drainage ravines of El Bats and El Wadi are, through a large part of their courses, cut down to the underlying Eocene rocks (Ravine beds), and in every locality examined the strata were found in the position they would be expected to occupy if undisturbed by tectonic movements. [Sidenote: Deep boring at Medinet el Fayûm.] The evidence yielded by the deep boring at Medinet el Fayûm is, as far as it goes, to the same effect. The ground level at the site was at 23·40 metres above sea-level and the following beds were passed through[28]:— Metres. Alluvial clays, clayey sands and sands, the latter in part coarse and pebbly 18·5 Yellow, brown, and grey marls and marly clays (probably belonging for the most part to the Ravine beds) 112·5 Cement coloured stone } 43·5 } Yellowish stone } Probably these 6·5 } limestones and Light brown solid stone } occasional marls 10·5 } and clays belong Cement coloured soft clay } to the Rayan series. 1·7 } Cement coloured stone } 12·5 ----- 205·7 ----- Bottom of boring 182·3 metres below sea-level.