46 Revieivs — Petroleum Resources of tlie Britisli Empire. 



to the nepheline-syenites described by Washington as foyaites and 

 ditroites. 



A great number of types of dykes have been distinguished showing 

 a range from paisanites to camptonites. 



With regard to the structure of the area three main faults have 

 been distinguished, and there is a great deal of minor faulting. 

 The main folding apparently took place a short time before the 

 intrusion of the alkaline batholith. 



Shatter-breccias are well-developed at the margins of the 

 intrusions, but there is little evidence of marginal assimilation 

 producing variation at the edges of the batholith. There is, however, 

 a great deal of assimilation producing hybrid rocks by the 

 commingling of two types, and descriptions are given of hybrids 

 developed at the junction of the alkali and calc-alkali series. It 

 is shown that extensive hybridism is not confined to interaction of 

 magma and cognate xenoliths, but may take place between magma 

 and relatively cold country rock. 



J. E. A. W. 



Imperial Institute : Monographs on Imperial Resources 



WITH special reference TO THE BRITISH EMPIRE : 



Petroleum. Prepared jointly with H.M. Petroleum Depart- 

 ment, with the co-operation of H. B. Cronshaw, B.A., Ph.D. 

 pp. x+llO. London : John Murray, 1921. Price 55. net. 



1\/rUCH literature has appeared in the past few years in connection 

 ■^^-*- with the petroleum resources of the world, both in this country 

 and America, but being of a decidedly popular or commercial 

 nature, it has usually suffered from the lack of scientific treatment. 

 The time is undoubtedly propitious for the publication of an official 

 volume (at a reasonable price) giving a concise and straightforward 

 account of the known occurrences of oil, and indicating also the 

 chief geological, physical, and chemical factors involved in each 

 instance. Such a monograph as this should naturally command a 

 wide circulation, and having a distinct educational value, we welcome 

 its appearance accordingly. 



While essentiall}^ a compilation, the book is not simply a mass of 

 incoherent facts ; those responsible for the text have been careful 

 to avoid mere tabulation by prefacing the descriptive sections 

 with an introductory chapter dealing with the characteristics, 

 occurrences, mining, refining, and uses of petroleum. The world's 

 resources are then discussed under two main headings, those of the 

 British Empire (including Mandatory Territories), and those of 

 foreign countries. In the former case, apart from the well-known 

 fields, such as Burma, Egypt, and Trinidad, much up-to-date 

 information is given concerning prospects in regions of which less 

 is known of their oil potentialities ; these comprise among others 

 Malta, Cyprus, Mesopotamia, Palestine, British Cameroon, Sudan, 

 Nigeria, Somaliland, and British Guiana. Such data is of the greatest 



