The Relations of the Eocene and Cretaceous Systems in the Esna-Aswan Reach of the Nile Valley

Abstract

I n the autumn of 1904 I had occasional opportunities of examining the desert-margins on both sides of the Nile Valley, between Aswan and Esna. The geological information hitherto published on this part of Egypt is so scanty that no apology is needed for putting on record the following observations, which, although disconnected, have an important bearing on a somewhat vexed question of Egyptian geology, namely, the mutual relations of the Cretaceous and Eocene systems. (1) The Kom-Ombo Plain. From Aswan to Darau the valley is comparatively narrow. Immediately north of the latter place it opens out, from a narrow gorge closed in by sandstone-hills, to a broad plain bounded by an undulating sandstone-desert on the west side, and by the ordinary sandstone-hills on the east: the latter running round in a wide curve, and not approaching the river until Jebel Silsila, 30 kilometres (sixteen and a half miles) farther north, is reached. In the centre of this area, on the eastern bank of the river, is the temple of Kom Ombo, from which the plain takes its name. As has long been recognized, the plain is superficially an extensive alluvial deposit; in addition to the sands and clays, with fluviatile shells and occasional mammalian bones, bands of tufaceous limestone are met with in the neighhourhood of Fatira. These deposits cannot be classed with the recent Nile alluvium, as they belong to the period of the great Pleistocene lakes of the Nile Valley, and have their surface some 25 metres (82 feet) above the