accumulation of the shells and skeletons of its denizens gave rise to the ooze, which has since hardened into chalk and nummulitic limestone. And it is quite certain that the whole of the area now occupied by Egypt, north of Esneh, and probably all that north of Assouan, was covered by tolerably deep sea during the cretaceous epoch. It is also certain that a great extent of dry land existed in South Africa at a much earlier period. How far it extended to the north is unknown, but it may well have covered the area now occupied by the great lakes and the basins of the White and Blue Niles. And it is quite possible that these rivers may have existed and may have poured their waters into the Northern Ocean, before the elevatory movement—possibly connected with the outpour of the huge granitic masses of the Arabian range and of Nubia—commenced, which caused the calcareous mud covering its bottom to become the dry land of what is now the southern moiety of Upper Egypt, some time toward the end of the cretaceous epoch. Middle and Northern Egypt remained under water during the eocene, and Northern Egypt during the commencement, at any rate, of the miocene epoch; so that the process of elevation seems to have taken effect from south to north at an extremely slow rate. The northward drainage of the equatorial catchment basin thus became cut off from the sea by a constantly increasing plain sloping to the north. And, as the plain gradually rose, the stream, always flowing north, scooped the long valley of Nubia and of Egypt, and probably formed a succession of deltas which have long since been washed away. At last, probably in the middle, or the later part, of the miocene epoch, the elevatory movement came to an end, and the gulf of the delta began to be slowly and steadily filled up with its comparatively modern alluvium.
Thus, paradoxical as the proposition may sound, the Nile is not only older than its gift, the alluvial soil of Egypt, but it may be vastly older than the whole land of Egypt; and the river has shaped the casket in which the gift lies out of materials laid by the sea at its feet in the days of its youth.
The fourth problem of Herodotus—the origin and the antiquity of the Egyptian people—is much more difficult than the other three, and I can not deal with it at the end of a discourse which has already extended to an undue length.
But I may indicate a few cardinal facts which bear on the discussion.
According to Figari Bey's investigations, a marine deposit, which probably is of the same age as the miocene beaches of Cairo and Memphis, forms the floor of the delta. Above this, come the layers of sand with gravel already mentioned, as evidencing a former swifter flow of the river: then follow beds of mud and sand; and only above these, at three distinct levels, evidences of human handiwork, the last and latest of which belong to the age of Ramses II.