The geological survey of the desert surrounding the Fayûm was commenced in October 1898. At that time the area, although so near to Cairo, was little known; the Rohlfs Expedition maps marked the region as “unexplored,” and in fact with the exception of a publication by Schweinfurth, who had traversed the region from north to south, via Qasr el Sagha and Gar el Gehannem to Rayan, there was little information obtainable. The area being of considerable size (12,000 sq. kilom.) and almost unexplored, both geologically and topographically, the primary object was to construct as rapidly as possible a general map of the depression, at the same time laying down in broad outline the chief geological formations and trusting to future opportunity to examine in more detail places of special interest.
Commencing work at Sêla, on the eastern side of the depression, the survey was carried northwards along the east side of the cultivated lands and thence through the northern desert, up to the summit of the depression. After mapping westwards as far as the isolated hill-mass of Gar el Gehannem the work was temporarily suspended until, in the spring, the narrow defile of Wadi Muêla, and the Wadi Rayan, forming the southern part of the Fayûm depression, were provisionally examined.
In January 1901, samples of soil and water from the cultivated lands were collected as an experimental soil-survey, and the results have been published.[1]
During the winter’s work of 1902-03 a traverse was carried from Gar el Gehannem in a south-west direction through a hitherto unexplored part of the depression. On reaching a point midway between Cairo and the oasis of Baharia a connection was made eastwards to Wadi Rayan. In the winter of 1903-04 further exploration was carried out in the neighbourhood of Gar el Gehannem.
It will be convenient here to briefly relate the history of the discovery of the remarkable series of new and extinct animal forms, the recovery of which from the Fayûm deposits has created such widespread interest in the zoological world. When Schweinfurth crossed the region in 1879 he obtained fossil bones, which were examined and determined by Dames to be the remains of cetacea of the genus Zeuglodon, from certain beds of the escarpment west of Qasr el Sagha; these, it is believed, were the earliest vertebrate remains obtained from the Fayûm. During the early part of the survey of the district, remains of fish and crocodiles were frequently found in one of the beds of the Middle Eocene, probably on the same horizon as that from which Schweinfurth had collected. Fragments of bone were also commonly met with on a much higher horizon (i.e., near the base of the Fluvio-marine series) but nothing of particular interest was obtained, as no detailed search could be made at that time. In April 1901, during the survey of the western end of the Birket el Qurûn, some of the localities found to be bone-bearing in 1898 were re-visited in company with Dr. C. W. Andrews, who was in Egypt at the time and had accompanied the survey in order to obtain specimens of jackals, hares, etc., for the British Museum, in connection with the forthcoming work on Egyptian mammals. In one of these Dr. Andrews picked up several vertebrae which turned out to belong to a new species of Pterosphenus.
Further north, when descending the Middle Eocene escarpments at a place not previously examined, we crossed the outcrop of the bone-beds at a point where a considerable number of mammalian and reptilian bones lay exposed on the surface, many in an excellent state of preservation. The importance of the find was evident, and a short examination of the material on the spot enabled Dr. Andrews to pronounce the discovery to be of the highest importance from a palaeontological point of view.
Some three weeks’ work in the immediate neighbourhood resulted in a very good collection of vertebrates from the Middle Eocene beds, including several new genera afterwards described[2] under the names of Eosiren, Barytherium, Mœritherium, Gigantophis, etc. Moreover, a fossil tooth brought in by one of the camelmen from a point several kilometres to the north led to a careful examination of the lower beds of the overlying Upper Eocene formation, which resulted in obtaining well-preserved remains belonging to a new genus, since described as Palaeomastodon. All the material so far obtained was taken home to be worked up and determined at the British Museum and a preliminary description was published by Dr. Andrews in the Geological Magazine.
In the winter of 1901-02 the survey of the Fayûm was resumed with the special intention of following up the highest beds, those in which Palaeomastodon had been found. Continued search westwards eventually led to the discovery of the remains of a large and remarkable horned ungulate (Arsinoitherium), a preliminary notice[3] of which was published in the spring of 1902. Shortly after, the remains of several new smaller mammals and reptiles (Phiomia, Saghatherium), including the shell of a large land tortoise (Testudo Ammon), were obtained[4]. Further work in the winters of 1902-03-04 led to a great deal more material being obtained[5], mostly of course belonging to the same species, but including some new genera Geniohyus, Megalohyrax, Pterodon.
The amount of palaeontological material is now so large that the Egyptian Government has arranged with the Trustees of the British Museum for the publication of the whole in a monograph to be issued by the Trustees. The present report, therefore, deals only with the geology and topography of the district.