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chrons with a reference growth curve are meaningful. The fact is that deposits of even a restricted type, age and province, such as volcanogenic massive sulphide deposits, show significant dispersion of Pb isotope ratios, reflecting a range of source U / P b values, and a single reference curve thus has only very general significance. The discussion of ore genesis (lead sources) on pages 161-163 could have been greatly improved by reference to Robertson's (1973) data for Zimbabwe gold deposits, noted elsewhere, and to other references cited in Chapter 3. In discussing identification of specific lithologic sources of lead (Chapter 9 ), primarily by feldspar and whole-rock Pb isotope analyses, no relationships to evolution models are noted. The text is remarkably free of typographical errors and is generally very readable and well illustrated. In places, however, editorial improvements in expression would have been helpful. The price of the volume is high in view of its production from typescript. In summary, this book is a must for the reading list of specialists in the isotope geochemistry field and those with an interest in possible applications of lead isotope studies, especially in exploration, but also in modelling, ore genesis, and crustal evolution studies. Concerning isotopic systematics and models, I suggest the interested reader consult, in addition to this volume, Kanasewich (1968), Doe (1970) and Faure (1977), all of whom have been cited by Gulson. The price of the volume, especially in relation to its size, will likely restrict its purchase to institutional libraries, companies serious about using Pb isotopes in exploration, and "experts" in isotopic studies. R.I. THORPE (Ottawa, Ont., Canada)

Marine Mineral Exploration, by H. Kunzendorf (Editor). Elsevier Oceanography Series 41. Elsevier, Amsterdam, The Netherlands, 1986, 300 pp., DF1. 160.00, US$ 59.25~ This book purports to deal with exploration techniques for marine minerals, but is, in reality, a general treatise on marine survey techniques some of which are applicable to marine minerals and some are not. After a general introduction, chapter 2 deals with the nature of marine minerals. This is followed by a chapter on research vessels and submersibles which is rather out of place in a book which otherwise deals mainly with geology and geophysics. Furthermore, of five examples of vessels given, only one is actually used in marine mineral exploration, which provides a good example of my general comment in the first paragraph of this review. Chapter 4 deals with marine geophysical exploration techniques in a fairly rigorous fashion, but again the

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authors did not seem to have marine minerals specifically in mind when they wrote it, as multichannel seismic and marine gravity, for example, have little or no application in marine minerals exploration. Chapter 5, which is entitled marine geochemical exploration methods, simply describes seawater and seafloor sampling devices and the chemical techniques used to analyse the samples that they obtain. Geochemical exploration in the sense understood by exploration geochemists is only briefly mentioned. Chapter 6 is one of the few chapters that does draw most of its material from actual marine mineral exploration programmes and deals with the statistical analysis of marine minerals data as and aid to exploration for and assessment of the deposits. The penultimate chapter is perhaps the most useful in the book in that it describes actual marine mineral exploration programmes in an authoritative manner. The application of techniques which should have been described in more detail in earlier chapters are detailed here. The final chapter, like Chapter 3, seems rather out of place, dealing as it does with law rather than minerals, but provides a useful review of the current situation in regard to the Law of the Sea. In my view, any marine mineral exploration effort should be soundly based on scientific principles, as derived from oceanographic research. It will simply not be possible to explore the whole ocean floor for minerals using the empirical techniques described in most of this book in anything like a reasonable time. Deductive exploration techniques are essential, and these are based on oceanographic science providing a knowledge of how and why the minerals vary as they do. In other words, science and exploration cannot reasonably be separated in the search for marine minerals. D.S. CRONAN (London, U.K.)

Serpentine and its Vegetation: A Multidisciplinary Approach, by R.R. Brooks. Dioscorides Press, Portland, Oregon, 1987, 454 pp., US$39.95. In 1972, R.R. Brooks wrote the first book outside of the Soviet Union that dealt with biogeochemical prospecting for minerals. His new text is another "first" in that a quantitatively small, yet economically valuable, body of rocks has been isolated for detailed examination of the chemistry and ecology which give rise to specific floral communities. Subsequent discussion relates the significance of these communities to the presence of mineralization. From a geological standpoint, the title of the book is rather a misnomer. It covers not only serpentine, but ultramaflc rocks in general. Brooks points out (p. 5 ) that "botanists (always refer) to ultramafic floras as 'serpentine floras', whether the soils are derived from serpentinized rocks or not". Since the declared aim of this comprehensive text is to reach a wide spectrum of scientists