SECTIONS. XIX. — From the Birket el Qurûn through Dimê and Qasr el Sagha to the summit of Jebel el Qatrani end XX. — From Wadi Rayan to the summit of the escarpment north of Gar el Gehannem „ XXI. — The Desert Ridge separating the Nile Valley and the Fayûm „ XXII. — From Sidmant el Jebel in the Nile Valley through Medinet el Fayûm to the summit of Jebel el Qatrani, near Widan el Faras „ XXIII. — Middle Eocene escarpment near Qasr el Sagha „ XXIV. — From Garat el Esh to summit of Jebel el Qatrani „ FIGURES (IN THE TEXT.) 1. — Fault near Qasr el Sagha 32 2. — Section at Gar el Gehannem, showing the relation of the Wadi Rayan series to the Ravine Beds 38 3. — Sketch-section across El Bats, one kilometre west of Sêla 40 4. — Profile of beds of Geziret el Qorn 44 5. — Section of cliffs, western end of the Birket el-Qurûn 47 6. — Probable course of chief river of Upper Eocene and Oligocene times 67 7. — Block of sandstone pierced by numerous borings 72 8. — Sketch showing relations of the Eocene to Pliocene gravel terraces on the east side of the Fayûm 74 9. — Sketch-section through the summit of the Fayûm escarpment at Elwat Hialla 76 10. — Sketch-map showing approximately the site of Lake Mœris 83 INTRODUCTION. * * * * * 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.