Reviews — Egypt from Cairo to Suez. 521 



The author divides the book into three principal parts. In the 

 first he gives useful hints as to the most suitable course of study, and 

 includes a description of the simple apparatus and reagents required. 

 A brief discussion follows on the nature of the interior of the Earth 

 and the character of its crust, and some of the differing hypotheses 

 that have been put forward. The second part is occupied with the 

 minerals that are of importance in the formation of rocks. The 

 author commences by rehearsing the physical and chemical properties 

 which admit of ready determination, and proceeds to describe concisely 

 the characters of the important species, grouped together as silicates 

 and oxides, hydrous silicates, carbonates, and sulphates. In the next 

 chapter he gives some simple chemical tests, such as need no elaborate 

 apparatus, and the part ends with two valuable tables for the 

 identification of minerals : the first, which is based upon the most 

 obvious physical characters, such as cleavage, streak, transparency, 

 and hardness, and comprises about thirty species, is intended for use 

 in the field; while the second, which is based in addition upon the 

 ordinary blow-pipe reactions, and includes about fifty species, should 

 preferably be employed whenever the additional tests can be made. 

 The third and last is the main part of the book, and, indeed, fills two- 

 thirds of the total number of pages. It is occupied with a full 

 description of the various kinds of rocks, divided into the three great 

 groups, igneous, stratified, and metamorphic rocks, and with a dis- 

 cussion of their classification. For each rock the author gives the 

 composition, properties, occurrence, uses, and relation to other rocks, 

 and at the end adds a useful table for the determination of rocks from 

 their most obvious characters. A copious index, in which the names 

 of rocks are italicised, brings the book to a close. 



Mention must not be omitted of the numerous admirable illustrations 

 which add so much to the value of the book. The reproductions 

 from photographs have been printed as plates, and are exceptionally 

 clear and distinct. 



G. F. H. S. 



lY. — Egypt. 



The Topograph r and Geology of the District between Cairo and 

 Suez. By Thomas Barron. 8vo ; pp. 133; maps and plates. 

 Cairo (Survey Department), 1907. 



THIS fine memoir has been printed just as it left the hands of its 

 lamented author. Opening with a chapter on the topography 

 of the region, full of interesting matter on meteorology and water 

 supply, vegetation and zoology, botany and inhabitants, the author 

 describes the Pleistocene, Miocene, Oligocene, Eocene, and Cretaceous 

 beds, their fossils, etc. The basaltic flows, necks, and sheets are dealt 

 with in chapter vii, and are recognised as Oligocene and of the same 

 age as those seen south-west of the Giza Pyramids. The faults and 

 folds of the area are fully described in chapter ix, one of 55 metres 

 and another of 165 metres being especially mentioned. The final 

 chapter (x) deals with the relief of the ground, and discusses at 

 length the denudation, agents of sculpture, sand action, sand-blast, 



