200 D)\ W. F. Hume — Geology of Eastern Sinai. 



The conclusion arrived at is as follows : — To the toest of a north- 

 south, line (practically longitude 34° E.) extend a series of N.W.- 

 S.E. rifts, the Suez type, which include not only the Western Sinai 

 valleys and the Gulf of Suez, but also Wadi Qena, and in all 

 likelihood part of the Nile Valley itself; while to the east of 

 this line is an Akaba rift-series, not only giving rise to the Gulf 

 of Akaba, but to all the important longitudinal valleys of Eastern 

 Sinai, and probably producing effects on the opposite coast of 

 Midian comparable for extent and interest to those of Egypt itself. 

 A third, or transverse, type of dislocation is also considered, special 

 attention being called to the regularity and parallelism of the valley 

 directions. Thus, in a space north of the transverse divide, the 

 valleys run mainly east-of-north, west-of-south, or north-east, while 

 in other parts of the eastern side of the peninsula the dominant trend 

 is slightly east-of-north, west-of-south, or south-east. On the western 

 side, on the contrary, they run north-west and south-east, or south- 

 west. Many of these transverse valleys a:-e in places deep clefts, 

 bounded by precipitous rock-walls, but the geological evidence of 

 rifting is wanting. The general conclusion is thus stated, after 

 a summary of the leading results : — The principal features of 

 Southern Sinai have been produced by dislocation rather than 

 erosion, fracture in three directions, either directly proved or in 

 the highest degree probable, having determined the general struc- 

 ture of the country. It is, in fact, the meeting-point of two great 

 longitudinal rift-systems, parallel to the Gulf of Suez and Gulf of 

 Akaba respectively, traversed by a third or transverse tyj)e, the 

 result being the apparently intricate maze of sharp crest and deep 

 valley characteristic of this region. 



Note. — It should be observed that the Akaba system of rifts does 

 not extend far south of lat. 28° N., the ranges to the east of the Eed 

 Sea being apparently also of the Suez type. 



IV. — Geology of Eastern Sinai.^ 



By W. F. Hume, D.Sc, A.E.S.M., F.G.S., etc. 



rpHE paper under consideration deals briefly with the geological 

 JL features of Eastern Sinai, and more especially with the 

 characters of the sedimentary rocks developed in that region, 

 a short note on the igneous rocks being also appended. The subject 

 is treated under the following headings : — 



I. Pebble Gravels, Travertine, etc. 

 II. Coral Eeefs. 



III. Cretaceous Limestones of Cenomanian age. 



IV. Nubian Sandstone. 

 V. Igneous Eocks, etc. 



I. Pebble Gravels. — Attention is here again called to the 

 remarkable development of high gravel terraces in the principal 



1 Eead by jDermission of tbe Egyptian Government before the International 

 Geological Congress, August, 1900. ' 



