Hugh J. L. Beaclnell — The Fayion Depression. 545 



the series may be regarded as Upper Eocene, while the higher beds 

 above the interbedded basalt marks the base of the Lower Oligocene. 

 It seems probable that this age - determiuation will hold good, 

 although whether it will ever be possible to draw a precise junction 

 between the Eocene and Oligocene is more than doubtful. The 

 series is quite continuous in the field, and the passage from the 

 one to the other formation appears to be perfectly gradual, both 

 lithologically and palEeontologically. 



Occasional fragments of bone may be observed in many parts 

 of the series, but, so far, the only remains of value obtained were 

 unearthed from the lowest bed, and are thus certainly of Upper 

 Eocene (Bartonian) age. The most important terrestrial animal 

 is FalcBomastodon Beadnelli, Andr., a small generalized form of 

 proboscidean, and probably a direct descendant of Mcerithium Lyonsi 

 of the Qasr el Sara series below. Part of the mandible of another 

 and different ungulate was also obtained, but has not yet been 

 determined. In addition, remains of crocodiles and turtles are not 

 uncommon in the basal beds of the ' Fluvio-marine Series.' The 

 post-basalt portion of the series forms the highest part of the 

 escarpment on the north of the Fayum depression. These beds 

 cover the desert to the north, stretching to beyond the latitude of 

 Cairo. To the north-west, however, they appear to pass gradually 

 up into younger deposits, as at Mogara Lower Miocene rocks occur. 



Space does not permit of any details being given here of the 

 younger Tertiary and Post-Tertiary Fayum deposits. 



General Eemarks. 



The Eocene rocks of the Fayum are of special importance, owing 

 to the presence in them of a new and highly interesting succession 

 of vertebrate remains, enabling us to gain some insight into the 

 nature of the fauna at that time inhabiting the great Atjican land- 

 mass to the south. In the region to the west of the iSile Valley, 

 comparatively shallow water existed from probably the beginning of 

 the Middle Eocene, and numerous rivers entered the sea in this 

 neighbourhood, bringing quantities of forest trees and floating 

 carcases of animals from the south. To the east deeper water must 

 have existed, as limestones continued to be accumulated until the 

 latter part of the Middle Eocene period, and even then the amount 

 of land sediment deposited was much less than in the Faytim. 

 Later, in Upper Eocene times, while the Fayum appears to have 

 been the site of an enormous delta, no deposits of the same age 

 at all appear to have been laid down to the east of the present 

 Nile Valley, as there the top beds of the Middle Eocene (Upper 

 Mokattam) are unconformably overlain by the Oligocene deposits 

 of Gebel Ahwar, etc. 



It is to be hoped that further exploration in the Fayum and 

 surrounding desert regions may in time lead to palaeontological 

 discoveries of the highest importance. Some of the primitive 

 ancestors of the proboscidea have already been discovered, and it is 

 not improbable that in the still lower Rayan series earlier and still 



DECADE IV. — VOL. VIII. — NO. XII. 3.) 



