Dr. A. L. Adams on the Geology of the Nile Valley. 551 



author's determination, enabled him to distinguish four genera, two 

 of which are new, and allied to Acrolepis and Platysomus respect- 

 ively; the known genera being Urosthenus, Dana (allied to Py- 

 gopterus), and Palceoniscus, Agass. Sir Philip was of opinion that 

 these genera were sufficient to stamp the deposit in which they 

 occur — namely, the Coal-formation of New South Wales — as be- 

 longing to the Palaeozoic period, if they may be regarded as repre- 

 sentative genera living at the same period as, but geographically 

 distant from, their nearest allies ; but, as regards the actual age of 

 the formation, the allied genera are more abundantly represented in 

 the Magnesian Limestone and the Kupferschiefer than in the Coal- 

 measures ; the materials were, he considered, too meagre to justify 

 a conclusion. 



2. "Notes on the Geology of a portion of the Nile Valley north 

 of the Second Cataract, in Nubia, chiefly with the view of inducing 

 further search for Fluviatile Shells at High Levels." By A. Leith 

 Adams, A.M., M.B., Surgeon 22nd Regiment. With a Note on the 

 Shells, by S. P.Woodward, Esq., F.G.S.; and a Note on some 

 Teeth of Hippopotamus, by Hugh Falconer, M.D., F.R.S., F.G.S. 



In company with the late Mr. A. H. Rhind, F.S.A., the author 

 made the usual boat-voyage from Cairo to the Second Cataract 

 during last November and the two following months, when he was 

 enabled to make some observations on the geology of that portion 

 of the Nile Valley. In this paper he first described the physical 

 features of the district, beginning at Selsileh and proceeding south- 

 wards, and then the lithological and stratigraphical characters of 

 the Nile sandstone, as well as its mode of junction with the granite, 

 noticing also the evidences of the Nile having shifted its bed, and of 

 other physical changes occurring in Nubia. Near the Second Cata- 

 ract were abundant proofs of the river having formerly flowed at 

 higher levels, the author having found river shells, such as Cyrena 

 fluminalis, Paludina bulimoides, Iridina Nilotica, and (Etheria semi- 

 lunata (the Nile Oyster), as also Bulimus pullus and a Unio like 

 U. pictorum, in beds of alluvium on elevated plateaus at various 

 heights, ranging up to 130 feet, above the highest inundations of 

 the present day. 



Dr. Adams concluded from these facts that the Nile was formerly 

 a more rapid river than it is now, and that the force and wearing 

 power of the stream has been steadily declining since the upheaval 

 of the valley ceased. 



The determinations of the shells were made by Mr. Woodward, 

 who gave a complete list of them in a Note. Dr. Falconer also 

 described two molars imbedded, in situ, in a fragment of the left 

 maxillary of a very large Hippopotamus ; the specimen was dug up 

 near the old Temple of Kalabshe, in Nubia ; and Dr. Falconer was 

 of opinion that it belonged to the same species as the existing Hip- 

 popotamus of that country. 



