128 Notices of Memoirs — II. J. L. Beadnell — Geology of Egypt. 



■ of the surrounding ridges, are found extensive raised beaches, 

 probably of marine Pliocene age, at which time the sea stretched 

 far up the Nile Valley. 



'Nile Valley. — la conclusion, some highly interesting facts are 

 brought forvvai'd with regard to the Nile Valley itself, which the 

 author summarizes as follows: — "The general north and south 

 direction of the Nile Valley in Egypt, the remarkable high, lofty, 

 wall-like cliffs by which it is hemmed in, the absence of any true 

 river deposits at any considerable height above the river, the almost 

 •entire absence of hills or outliers of the plateau within the valley, 

 the proved existence of bounding faults throughout a long stretch 

 of the valley, lead us to infer that the formation of this gorge was 

 brought about by faulting, rifting, and folding, and not cut out in 

 the usual way by river action." 



Between Cairo and Assuan the Nile Valley floor is covered for 

 the most part with deposits of comparatively recent geological age, 

 which may be divided into (1) Marine, Pliocene ; (2) Lacustrine, 

 Pleistocene ; and (3) Fluviatile, Recent. 



The marine Pliocene deposits, discovered near Esna by Mr. Barron 

 and the author in 1897, consist of a thick series of limestones and 

 interbedded conglomerates. In the limestones numerous foraminifera 

 were found, and have been described by Mr. F. Chapman. 



The lacustrine series consist of fresh-water deposits of the most 

 variable nature, including gravels, conglomerates, clays, marls, lime- 

 stones, and tufas. They have been mapped and examined by the 

 author throughout a large length of the Nile Valley from Qena to 

 Cairo. Calcareous tufas, crowded with the most beautiful impressions 

 of leaves and twigs, abound in places. At Isawia the limestones of 

 the series are of considerable commercial importance, supplying the 

 material for the construction of the great dam at Assiut. Finally, 

 the fluviatile deposits include the Nile mud and other recent 

 accumulations. 



In conclusion, the author shows the probable date of the formation 

 of the Nile Valley gorge to be Lower Pliocene, and refers it to the 

 same great series of earth-movements which determined and formed 

 the main physical feature of North-East Africa and part of Asia. 

 After the deposition of the Pliocene beds a gradual elevation led to 

 the final retreat of the sea, the valley then becoming the site of 

 a series of fresh-water lakes in which were deposited large quantities 

 of calcareous tufa, which enclosed the numerous leaves carried into 

 the lakes from the surrounding forests. 



Finally, "in later Pleistocene times drainage must have become 

 well established down the Nile Valley, and a river, the youthful 

 Father Nile, commenced its cai'eer by carving out a channel through 

 the valley deposits, before, owing to changed conditions, it finally 

 •took to depositing layer upon layer of ' Nile mud,' thus forming the 

 :strip of cultivable and inhabitable country without which the Land 

 •of Egypt, as we know it, would be non-existent." 



