most common form in the Dicotyledonae but, unlike grass phytoliths, there are few descriptions and illustrations of these or any other dicot products. The formation of phytoliths is not common in gymnosperms, although several types showing characters of taxonomic significance have been reported in Pinus, Picea, Luni (misspelt Larex in the text) and Pseudotsugu. It also appears to be confined to relatively few groups of ferns and allied plants; Dr Piperino names the Polypodiaceae, Hymenophyllaceae, Selaginellaceae and Equisetaceae. Phytoliths have rarely been recorded from Cretaceous sedimentary deposits or encountered in the fossil plants contained therein. They must inevitably have only limited value in palaeobotanical and palaeoecological studies of the remains of vegetation of this age. In common with many Cretaceous palynomorphs, most may well prove to be identifiable only as morphological entities owing to a lack of suitable comparative modern or fossil reference material. This is a direct reflection of the composition of the vegetation of the period which was dominated by pteridophytes and gymnosperms until the Late Cretaceous, and even then, many of the angiosperm fossils that have been found belong to groups of plants that are now extinct. For those palaeontologists who are interested in learning about phytoliths and how they might be used in future research projects, this book is, however, worth reading. It brings together under one cover much of what is currently known about the morphology of these siliceous bodies. It also includes sections on how they can be isolated from soils and sediments, and how they may be used in palaeoecological interpretations and archaeological reconstructions. Whether it will stimulate “the development of phytolith analysis as a more refined instrument of paleoecology” and “push the archaeological profession to a new level of understanding and greater use of phytolith-analytical studies”, as Dr. Piperino hopes (preface, p. x), remains to be seen. D. J. Batten Institute of Earth Studies UCW Abeqstwyth University of Wales Abeystwyth SY23 3DB ( UK
The Concise Oxford Dictionary of Earth Sciences A. & M. Allaby (editors), 1990, xxi + 410 0-19-866146-O.
pp., Oxford University Press, Oxford, f20 (hardback), ISBN
It must be difficult to compile a dictionary. It is essential that accurate and concise definitions of words are provided. The temptation to expand explanations into encyclopaedic discourses must sometimes be considerable, but needs to be avoided. In the majority of scientific subjects in which much research is being carried out, new words are constantly being introduced to the vocabulary, while the definitions of others become modified and some pass out of use or fashion. This inevitably means that the compilers of a dictionary must take great care over what to include and what to omit.
The editors of this volume on Earth Sciences, which here encompasses aspects of climatology, hydrology, meteorology and pedology, as well as the many fields of geological endeavour, almost certainly had to make numerous difficult decisions on content and presentation. They state in the preface that their aim has been a “dictionary proper” in which as many terms as possible are defined in as few words as is reasonable. Have they succeeded in doing this? The straight answer has to be “no”, but that is not to say the volume is not useful. It contains a wealth of information within its 410 pages but is not as comprehensive as I would have liked. At the same time, it includes quite a few words (particularly fossil genera and species) which could have been omitted. As an editor of Cretaceous Research it is inevitable that from time to time I have to reach for a dictionary to remind myself of the definitions of words I have forgotten, to discover the meaning of those that are new to me, or to check how they should be spelt. Among the terms encountered during the past year that I needed to look up were “ravinement surface”, “volcanoclastic” as opposed to “volcaniclastic”, “rhegmatic” and “loferite” (or lopherite), none of which is in this Concise OxjX Dictionary. In the process of using it I also discovered by chance that there are no entries for “lithographic limestone”, “epiplankton”, “palynomorph” and “Chitinozoa”. “Palynology” is listed; however, the definition not only extends beyond the realm of Earth Sciences but also is incorrect because the subject does not include the study of coccolithophorids . There is a surprisingly large number of entries for genera and species of animal and plant fossils. I question the need to include species because these can only be isolated examples of the huge number of taxa that have been described. It is perhaps marginally useful to insert the names of the oldest, smallest, largest, or most unusual examples of particular groups of organisms. This appears to be the reasoning behind some of the entries, but the logic of including others escapes me. I think the editors should have restricted their coverage of fossils mainly to families and higher taxonomic groups (e.g. Agnatha, Bacillariophyceae and Dendroidea), genera and, in exceptional circumstances, species only being named where appropriate as representatives of these groups. An inevitable consequence of the approach adopted here is that numerous anomalies have been created. Why, for example, add specific epithets to some genera (e.g. Cooksonia hemispherica) but not others (e.g. Coelophysis)? Why include Clavatipollenites, an early (but probably no longer the earliest known) angiosperm pollen grain and not Ambitispnites, one of the first spores in the fossil record to have possibly been produced by vascular plants? Anomalies are not, however, confined to fossils. Why make specific mention of the Clinton Ironstone? There are many other named ironstone formations for which there are no entries in the dictionary. Since the “Gault Clay” is included, why not the Austin Chalk or the Woodbine Formation? There is an entry for Marshbrookian, an Ordovician “stage”; why then are the Carixian, Clansaysian and Domerian omitted? Is it really necessary to include so many New Zealand stages, since these are now generally regarded as “local”? There are definitions of the Graptoloidea and Dendroidea, but not of the less common graptoiitic groups, such as the cameroids, crustoids and tuboids. There are entries for Francis P. Shepard and Edward Bullard but not for Harry Godwin, arguably equally as “famous” within the field of Earth Sciences. What about the definitions themselves? They vary greatly. Some are succinct (e.g. those for nappe and native element), some are verbose and may involve words for which meanings are not given therein or elsewhere in the dictionary (e.g. under
the entry for the Dinophyceae, the group to which this class of organisms belongs, the Pyrrhophyta, is mentioned but not defined anywhere), and some are virtually short essays on a particular subject (e.g. for “Koppen climate classification” and “initial strontium ratio”). Among the disappointments for me was the discovery that, for each of the organic components of coal, I was told to “see coal maceral” where they are in fact mostly defined in single sentences. Since the volume is supposed to be a dictionary why couldn’t these straightforward explanations have been recorded separately in their correct alphabetical location? There are many other entries that I could also comment on in a similar vein. Of course, it is easy to criticize. To be fair to the editors of, and contributors to, this dictionary, the volume does contain much valuable information and I am glad to have a copy. Since it is not, however, comprehensive it would be foolish of me to dispose of my other dictionaries. D. J. Batten Institute of Earth Studies UCW Abeymyth CJniversityof Wales Aberystzyth SY23 3DB, UK
Global climatic catastrophes by M. I. Budyko, G. S. Golitsyn and Y. A. Izrael, 1988, 99 pp., Springer-Verlag, Berlin, DM. 38,011.
In 1980, Luis Alvarez, Walter Alvarez, Frank Asaro and Helen Michel provided geochemical evidence for the impact of a large extra-terrestrial body on Earth at the end of the Cretaceous period, a time of mass extinction in the marine and terrestrial realms (Alvarez et al., 1980). Subsequent studies of extinction have concentrated on reconstructing environmental change during mass-extinction events and determining the extent to which extra-terrestrially driven perturbations of the physical environment can explain extinction patterns documented in the geological record (see papers in Donovan, 1989, for recent reviews). In 1982, Paul Crutzen and John Birks demonstrated the possibility of serious atmospheric consequences resulting from generation of a smoke cloud during a major nuclear exchange between the superpowers (Crutzen & Birks, 1982). Subsequent studies of “nuclear winter” have attempted to predict the environmental aftermath of a major nuclear exchange, largely through numerical modelling of the atmosphere and using the output of numerical models to predict biological and sociological consequences (see Schneider & Thompson, 1988, for a recent review). Together the fields of extinction science and nuclear winter modelling form part of a larger discipline that is perhaps best termed “global catastrophe science”. Global catastrophe science uses data from such diverse fields as astronomy, biology, climatology and geology to understand the nature of past, present and future catastrophic events. Global climatic catastrophes attempts to transcend the boundaries of individual scientific disciplines and provide a unified conceptual framework for understanding global catastrophes. The senior author, M. I. Budyko, is an internationally known scientist who has carried out pioneering research in the fields of climatology and hydrology, and is perhaps best known to readers of Cretaceous Research as the senior author of an earlier book, History of the Earth’s atmosphere. The junior authors, G. S. Golitsyn and Y. A. Izrael, are also internationally known climate researchers. All