Three symposia on environmental geochemistry in tropical countries, held in Niter6i, Brazil (1993), in Cartagena, Colombia (1996) and in Nova Friburgo, Brazil (1999), made it very clear that tropical geochemistry is of world standard and fast increasing in multi disciplinarily and impact on important geochemical paradigms. It has additionally strong links with the economy of tropical countries, such as mining and industrialisa tion and is in full development for treating environmental problems caused by human activities of urban or industrial origin. We must compliment Prof. Jorge Abriio and his colleagues in Brazil and Dr. Gloria Prieto and her colleagues in Colombia for these ini tiatives. The participation of respectively 180 and 150 scientists, coming from 15 different countries for the first and second symposia, has shown that a large interest exists for tropical environmental geochemistry. It also demonstrates the necessity to understand tropical environmental problems. The organisation of a large international symposium is not possible without the assistance of state and federal authorities, for which those of Brazil and Colombia have to be complimented. The 3rd Symposium on Environmental Geochemistry in Tropical Countries was the last of the series and was attended by 22 countries and 170 participants and treated a number of related environmental and economic problems."

Soil is formed from the physical and chemical weathering of rocks-processes described historically becau'se they involve eons of time-by glaciation and by wind and water transport of soil materials, which are later deposited in deltas and loessial planes. Soil undergoes further transformations over time and provides a habitat for biological life and a base for the development of civilizations. Soil is dynamic-always changing as a result of the forces of nature and particularly by the influences of man. Soil has been studied as long as history has been documented. Numerous references to soil are found in historical writings such as Aristotle (384-322 Be), Theophrastus (372-286 Be), Cato the E1der (234-149 Be), and Varro (116-27 Be). Some of the earliest historical references have to do with the erosional forces of wind and water. The study of soils today has taken on increased importance because a rapidly expanding population is placing demands never before experienced on the soil. This has led to an increase in land degradation. Land degradation is one of the most severe problems facing mankind. Volume 11 of Advances in Soil Science was devoted entirely to this critical area of soil science. This series, Advances in Soil Science, was established to provide a forum for leading scientists to analyze and summarize the available scientific information on a subject, assessing its importance and identifying additional research needs.

Landscapes of the past have always held an inherent fascination for ge ologists because, like terrestrial sediments, they formed in our environment, not offshore on the sea floor and not deep in the subsurface. So, a walk across an ancient karst surface is truly a step back in time on a surface formed open to the air, long before humans populated the globe. Ancient karst, with its associated subterranean features, is also of great scientific interest because it not only records past exposure of parts of the earth's crust, but preserves information about ancient climate and the movement of waters in paleoaquifers. Because some paleokarst terranes are locally hosts for hydrocarbons and base metals in amounts large enough to be economic, buried and exhumed paleokarst is also of inordinate practical importance. This volume had its origins in a symposium entitled "Paleokarst Systems and Unconformities-Characteristics and Significance," which was orga nized and convened by us at the 1985 midyear meeting of the Society of Economic Paleontologists and Mineralogists on the campus of the Colorado School of Mines in Golden, Colorado. The symposium had its roots in our studies over the last decade, both separately and jointly, of a number of major and minor unconformities and of the diverse, and often spectacular paleokarst features associated with these unconformities."

F. J. COLON Chairman of the Scientific Committee TNO Division of Technology for Society, APELDOORN, The NETHERLANDS Only these past few years have we gained an insight into the full extent of the problems associated with contaminated soils. The first efforts to take effective remedial action at contaminated sites were seriously hampered by the lack of experience, knowledge and technology. Fortunately, this handicap has been partly alleviated by the experience we have gained in the numerous cases we have had, and -unfortunately still have to deal with. This meeting on contaminated soil is the first international conference to cover such a wide variety of subjects related to the problems that confront us in practice: behaviour of contaminants in soil - impacts on public health and the enviornment - role of governments and other authorities - site investigation and analysis - techniques for remedial action - management of remedial action and risk assessment - safety - case studies This Conference has been organized by the Netherlands Organization for Applied Scientific Research (TNO) in co-operation with the Netherlands Ministry of Housing, Physical Planning and the Environment (VROM). It goes without saying that the preparation would not have been possible without the assistance of many people throughout the world and the co-operation between government, industry and research organizations."

The NATO Advanced Research Workshop from which this book derives was conceived during Biotec-88, the Second Spanish Conference on Biotechnology, held at Barcelona in June 1988. The President of the Conference, Dr. Ricardo Guerrero, had arranged sessions on bacterial polymers which included lectures by five invited participants who, together with Dr. Guerrero, became the Organizing Committee for a projected meeting that would focus attention upon the increasing international importance of novel biodegradable polymers. The proposal found favour with the NATO Science Committee and, with Dr. R. Clinton Fuller and Dr. Robert W. Lenz as the co-Directors, Dr. Edwin A. Dawes as the Proceedings Editor, and Dr. Hans G. Schlegel, Dr. Alexander J.B. Zehnder and Dr. Ricardo Guerrero as members of the Organizing Committee, the meeting quickly took shape. To Dr. Guerrero we owe the happy choice of Sitges for the venue, a pleasant coastal resort 36 kilometres from Barcelona, which proved ideal. The sessions were held at the Palau de Maricel in appropriately impressive surroundings, and invaluable local support was provided by Mr. Jordi Mas-Castella and by Ms. Merce Piqueras. Much of the preparatory work fell upon the broad shoulders of Mr. Edward Knee, whose efforts are deeply appreciated. The Organizing Committee hopes that this Workshop will prove to be the first of a series which will aim to keep abreast of a rapidly expanding and exciting area of research that is highly relevant to environmental and industrial interests.

Evapotranspiration and its components (evaporation and transpiration) as a process is one of the basic terms of Earth's water balance; its importance is accented by the fact that transpiration is the vital element of the biomass production process. The second important property of evapotranspiration is its extreme consumption of solar energy, thus controlling the temperature of the atmosphere and creating favourable conditions for life. Evapotranspiration as an energy consuming process is also the connection between the energy and mass cycles of the Earth. Evapotranspiration is a process performing in the Soil-Plant -Atmosphere System (SPAS); therefore this book is presenting and quantifying it as a catenary process, describing transport of water in the soil, including root extraction patterns and methods of its evaluation. Transport of water through the plant and from the canopy to the atmosphere is also described and quantified. A variety of evapotranspiration (and its components evaporation and transpiration) calculation methods are described, starting from empirical methods up to the most sophisticated ones based on the solution of the transport equations of water and energy in the SPAS. The most important (and widely used) calculation method - modified Penman-Monteith method is described in details, ready to be used with data in the book only. Water balance method of evapotranspiration estimation as well as sap flow method description can be found in the book as well. The book can be used by hydrologists, biologists, meteorologists and other specialists as well as byecology students.

Key themes: soil hydrology - evapotranspiration - hydropedology- plant physiology -water movement in soils -evaporation -transpiration

Dr. Viliam Novak isa water resources scientist at the Institute of Hydrology of the Slovak Academy of Sciences in Bratislava (Slovakia)."

The world needs for food and fiber continue to increase. Population growth in the developing countries peaked at 2. 4 percent a year in 1965 and has fallen to about 2. I percent. However, in many developing countries almost half the people are under 15 years of age, poised to enter their productive and reproductive years. The challenges to produce enough food for this growing population will remain great. Even more challenging is growing the food in the areas of greatest need. Presently the world has great surpluses of food and fiber in some areas while there are devastating deficiencies in other areas. Economic conditions and the lack of suitable infrastructure for distribution all too often limit the alleviation of hunger even when there are adequate supplies, sometimes even within the country itself. World hunger can only be solved in the long run by increasing crop production in the areas where the population is growing most rapidly. This will require increased efforts of both the developed and developing countries. Much of the technology that is so successful for crop production in the developed countries cannot be utilized directly in the developing countries. Many of the principles, however, can and must be adapted to the conditions, both physical and economic, of the developing countries. This series, Advances in Soil Science.

This volume presents the proceedings of the Second International Sym posium on Genetic Aspects ofPlant Minerai Nutrition, held in Madison, Wisconsin in 1985. The mechanisms by which plants acquire, transport and utilize essential minerai nutrients are highly complex. The means by which plants either exclude or tolerate ions of metals toxic to plants are equally complex. The first symposium attempted to convene research scientists con cerned with minerai nutrition for the purpose of exploring the kinds of minerai nutrition phenomena identified as being under genetic contro!. The first symposium also placed much emphasis on research to which genetic intervention might be applied. At the second symposium more papers were presented on genetic and breeding research, a long-term objective of the first symposium. The second symposium also included biotic interactions under genetic con trol that either enhanced or impeded ion uptake, e.g. mycorrhizae and nitrogen fixing bacteria. This continuing dialogue is essential for a research area the complexity of which is due to its interdisciplinary nature.

During the past few years there has been a marked increase in the use of advanced chemical methods in studies of soil and clay mineral systems, but only a relatively small number of soil and clay scientists have become intimately associ ated and acquainted with these new techniques. Perhaps the most important obstacles to technology transfer in this area are: 1) many soil and clay chemists have had insufficient opportunities to explore in depth the working principles of more recent spectroscopic developments, and therefore are unable to exploit the vast wealth of information that is available through the application of such ad vanced technology to soil chemical research; and 2) the necessary equipment gen erally is unavailable unless collaborative projects are undertaken with chemists and physicists who already have the instruments. The objective of the NATO Advanced Study Institute held at the University of Illinois from July 23 to August 4, 1979, was to partially alleviate these obstacles. This volume, which is an extensively edited and reviewed version of the proceedings of that Advanced Study Institute, is an essential aspect of that purpose. Herein are summarized the theory and most current applications of six different spectroscopic methods to soil and/or clay mineral systems. The instrumental methods examined are Mossbauer, neutron scattering, x-ray photoelectron (XPS, ESCA), nuclear magnetic resonance (NMR), electron spin resonance (ESR, EPR), and photoacoustic spectroscopy. Contributing authors were also lecturers at the Advanced Study Institute, and are each well known and respected authorities in their respective disciplines."

"Reviews of Environmental Contamination and " "Toxicology"contains timely review articles concerned with all aspects of chemical contaminants (including pesticides) in the total environment, including toxicological considerations and consequences. It attempts to provide concise, critical reviews of advances, philosophy, and significant areas of accomplished or needed endeavor in the total field of residues of these and other foreign chemicals in any segment of the environment, as well as toxicological implications.

Chemical pesticides continue as a point of major controversy in our society. Increasingly stringent regulatory actions on the part of state and federal agencies, exemplified by the RPAR (Rebuttable Presump tion Against Registration) program of the Environmental Protection Agency, are supported by environmental groups and are generally op posed or viewed with skepticism by agriculturalists. The energy crisis invokes other questions on benefits of pesticides versus nonchemical controls and effects on labor utilization. As DDT and other persistent pesticides have been phased out, the more labile, short-lived chemicals have filled the voids in pest management systems; and effects on nontarget species appear to have declined in recent years as the shift occurred. However, nagging ques tions of the hazard to man and other nontarget species from long-term, low-level exposure to pesticides are frequently raised; and recent suggestions that certain well-known and long-used chemicals cause cancer, increase sterility, and initiate or augment other deleterious effects in test animals have instilled a sense of caution and raised con cern about the continued availability of some pesticides previously considered safe. So the facade of concern and confusion continues. This book is an outgrowth of a symposium at the meeting of the American Association for the Advancement of Science in February, 1978. An introduction has been added, and some of the papers have been modified since presentation."

This book is the published record of the papers presented at a conference of the Norwegian Petroleum Society (NPF) held in Bergen, Norway, on 3-5 October, 1988. The conference was initially proposed and promoted by the Geology and Geophysics Advisory Committee of the Norwegian Petroleum Society consisting of: A. M. Spencer (Chairman), M. Brink,J. D. Collinson, S. Hanslien, D. M. D.James, T. B. Lund, K. Messel, E. Ormaasen and G. Saeland. The programme and more detailed planning of the conference was carried out by a programme committee consisting of: J. D. Collinson (Chairman), O. Eldholm, E. Holter, D. M. D.James, H. Tykoezinski, D. Worsley and S. M. Aasheim. There were 245 participants at the meeting and 36 papers were presented as talks with a further 9 presented as posters. These proceedings are representative of the range of topics covered. The meeting was characterized by a high level of discussion which has influenced several authors in the final preparation of their written papers. These proceedings have been edi ted on behalf of the Norwegian Petroleum Society by J. D. Collinson with help from H. Tykoezinski. The editor and the organizing committee wish to thank all the referees who reviewed papers and all the authors who responded so fully and promptly to their comments. The NPF is most grateful to the University of Bergen for making available their facilities for the conference.

Agricultural soils are subjected to many applied mechanical stresses that influence their behavior. Stresses arise from tillage machines, seeders and chemicals applicators, tractors, and equipment for harvest and transport. Applied stresses may compact or loosen the bulk soil. Micro sections of soil (aggregates or clods) may be compacted during tillage while the bulk soil is loosened. Because most granular soils are combined into structural units of varying sizes with different strengths and properties, prediction of the effect of stresses on the behavior of bulk soils is difficult. The basic strength properties of soil are determined by many fac tors: the size distribution of particles, chemical and mineralogical properties of inorganic clay fraction, the organic matter content and composition, the water content and the stress history. These factors combine and interact to produce many possible behavior patterns. Changes in structure of the soil from applied stresses and biologi cal reactions may profoundly influence storage and transmission of water, heat, and air, and the mechanical resistance to penetration by plant roots. They may also affect the traction of vehicles. Manipulation of structural properties of soils by tillage implements is a major cost under most crop production systems. Reduced energy use is also a significant conservation objective. Improved management systems are very dependent upon a better understanding of soils' response to applied stresses. The content of this book resulted from a NATO Advanced Research Workshop held in St. Paul, Minnesota, U.S.A. September 13-16, 1988."

This volume contains the Proceedings of the International Conference on Effects of Crop Rotation on Potato Production in the Temperate Zones. This conference was held in the International Agricultural Centre at Wageningen, The Netherlands, August 14 - 19, 1988, under the auspices of the European Association for Potato Research (EAPR), the Potato Association of America (PAA) and the Dutch National Council for Agricultural Research (NRLO). The length of rotations affect the performance of potato crops and yields are often reduced if rotations are too short. The kinds of crops within a rotation will also affect potato performance, especially those grown in the previous season. It was a major aim of the conference to bring together specialists of various disciplines to examine these determinants of potato yield. The Organizing Committee is glad that all relevant aspects of the theme are highlighted in these proceedings. The contents of the contributions are primarily left to the responsibility of the authors. J. Vos C.D. van Loon G.J. Bollen ORGANIZATION OF THE CONFERENCE The European Association for Potato Research (EAPR) and the Potato Association of America (PAA) nominated representatives in the Conference Committee. PAA was represented by prof. dr E.E. Ewing (Ithaca, USA) and by dr R.E. Thornton (Pullman, USA); EAPR was represented by prof. dr J.C. Holmes (Edinburgh, UK), ir C.D. van Loon (Lelystad, NL), and dr ir J. Vos (chairman; Wageningen, NL).

Fertilizer is a vital component of strategies for expanding foodproduction. The rapid growth in population and the widening food deficits inmany tropical countries of Asia, Africa, and Latin America call attention to those aspects of fertilization that have been neglected but are expected to yield large economic payoffs in the future. Fertilizer sulfur falls into this category. In the past fertilizer sulfur received little attention from researchers and policymakers since sulfur deficiency was not considered a serious problem. It was not a problem because of low crop yields, extensive cropping, and the incidental supply of sulfur through rain, irrigation water, manures, and sulfurcontaining fertilizers. However, the situation has changed in the last three decades. Moder nagriculture based on high crop yields, intensive cropping, improved crop varieties, and greater use of sulfur-free fertilizers and environmental regula tions restricting sulfur emissions are creating large gaps between sulfur sup ply and sulfur requirements. Sulfur deficiencies are widespread and grow ing. Consequently, the full potential of a modern agricultural system in tropical countries is not being realized. This research effort results from the recognition of the seriousness of the sulfur problem and its adverse impact on food production as well as IFDC's dedication to the development and transfer of economically ef ficient fertilizer technology to tropical countries. This study represents a comprehensive analysis of the technical and economic linkages between fer tilizer sulfur and food production, and it provides guidelines for future directions in fertilizer sulfur research and public policy."

This series is dedicated to serving the growing community of scholars and practitioners concerned with the principles and applications of environmental management. Each volume is a thorough treatment of a specific topic of importance for proper management practices. A fundamental objective of these books is to help the reader discern and implement man's stewardship of our environment and the world's renewable resources. For we must strive to understand the relationship between man and nature, act to bring harmony to it, and nurture an environment that is both stable and productive. These objectives have often eluded us because the pursuit of other individual and societal goals has diverted us from a course of living in balance and the environment. At times, therefore, the environmental manager may have to exert restrictive control, which is usually best applied to man, not nature. Attempts to alter or harness nature have often failed or backfired, as exemplified by the results of imprudent use of herbicides, fertilizers, water, and other agents. Each book in this series will shed light on the fundamental and applied aspects of environmental management. It is hoped that each will help solve a practical and serious environmental problem.

Plant-Microbe Interactions, Volume 1 Many plant-microbe interactions have agronomic importance because of either beneficial (e.g., nitrogen fixation or biocontrol) or detrimental (e.g., pathogen esis) effects. Although these systems have been the subjects of scientific re search for many years, recently there has been a tremendous increase in our knowledge of them. The increases in this research have followed a similar general increase in plant science research. Classical plant science research disciplines (e.g., agronomy, breeding, plant physiology, systematics, etc.) have been affected by an increased focus on molecular biology. These new technologies, as well as advances in other areas, have the effect of blurring the traditional borders between research disciplines. Another factor influencing the development of this research is the increased attention given to environmental issues. These concerns have been brought about by debate over the release of genetically modified organisms and the general concern over environmental quality. Thus, research areas focused on plant-microbe interactions are presently in a period of great excitement and growth that shows every sign of continuing far into the future. As in most research areas, the rate of advance and breadth of disciplines involved in the study of plant-microbe interactions make it impossible for the average researcher or student to stay abreast of the primary scientific literature."

The contentsof this volume representthe proceedings of the First International Symposium on Foliar Fertilization which was organizedby Schering AG Agro- chemical Division's Special Fertilizer Group on 12-14 March 1985. The conference was attended by 130 participants from 35 countries . As a leadingcompany in the field offoliarfertilizers , ScheringAG organizedthis conferenceto gathercurrentknowledgeon foliarfertilization under various crop and environmental conditions.We believe thatthese Proceedings form a basis for a more relevantapproach to foliarfertilization in agriculture and horticulture and thattheysummarize the currentstateof our knowledgeon this highly efficient methodof fertilization. Besides the formalpresentation of invitedfull-length papers, shortcommunications were also invited for presentation. Most of theseshortcommunicationshave been kindly expanded by their authorsto fullpapers. The subject matterhas been arrangedin these Proceedings to obtain a bettersequence than was originally possible in theprogramme for technicalreasons .: Chapter1 dealswith "Fundamental aspectsof foliarfertilizat ion". Chapter2 deals with "Foliarfert ilizationunder arid and semi-arid conditions", Chapter 3 is devoted to "Foliar fertil ization under tropicalconditions",Chapter 4 deals with "Foliar fertilization in horticulture" , Chapter5 is devotedto "Foliarfertilization in cerealcultivation" and Chapter6 concludeswith "Foliarfertilization in differentcrops and count ries". It is appropriatethata substantialportion of these proceedings is devoted to practicalaspects of foliarfertilization thus recognizingthe fact that foliarfer- tilizationhas gained an outstandingrole inagriculture and horticulture and will see even more inthe future. We express our special thanksto the chairmen of the various sessions who con- tributedto the su ccess of thesymposium: Professors E. Malavolta,M. Fregoni , T. Kudrev, H. -W. Doring, D. jelenic and Dr. V. Szirtes .

The fifth meeting of scientists working with Frankia and actinorhizal plants was held at Montmorency Forest of Laval University in Quebec from August 6-8, 1984. Results of research presented at the meeting are included in this special volume of Plant and Soil. The understanding of actinorhizal systems continue to increase, though work and use shops and discussions at this and similar meetings make it evident that this important subject remains open for fruitful investigation at all levels. Some important 'firsts' were reported at this meeting. The first extensive survey of Frankiae and their host specificity ranges from Asia was presented. This is of significance since Asia is a center of diversity for many actinorhizal host plant genera. A report that proto plasts of Frankia have been produced and regenerated for the first time improves the possibility for genetic manipulation of Frankia. It is also important to note the first report herein of successful mass inoculation of actinorhizal plants commercially for stabilization and reclamation of disturbed soils around hydroelectric power projects in Quebec. This heralds the transfer of actinorhizal technology to private and public users. The bacterial genus Frankia is easily recognized both in vivo and in vitro, and isolation of this organism has become routine. But, as yet, there are not sufficient biochemical, morphological, or anatomical criteria for establishing species."

Soil ecology is the study of interactions between the physio-chemical components of the soil and organisms living within the soil. Humans are highly dependent upon the soil ecosystem, which provides food, fiber, fuel and ecological services, such as the recycling of atmospheric gases. It is therefore important to understand the function and nature of the soil ecosystem in order to predict and mitigate the long term consequences of present day actions. Soil Ecology and Management describes the organisms inhabiting the soil, their functions and interactions and the dimensions of human impact on the activity of soil organisms and soil ecological function. Chapters discuss basic soil characteristics and biogeochemical cycling, key soil flora and fauna, community-level dynamics (soil food webs) and the ecological and pedological functions of soil organisms. Unlike other soil biology and ecology textbooks, the authors also convey a better understanding of how human activities impact upon soil ecology in a section on ecosystem management and its effects on soil biota and provide a unique perspective on the utility of soil organisms.

PH. BOURDEAU Directorate-General Science. Research and Development. Commission of the European Communities. Brussels. Belgium We are living on a unique planet, the only one in the solar system where life exists. The very existence of life has modified the physical and chemical environment of the earth, its atmosphere and oceans, in a way that makes life sustainable. This system with its complex cybernetic mechanisms has been named GAIA by Lovelock. Man has always interfered with it on a more or less limited scale. This interference is now reaching global proportions such as climate modifications resulting from CO and trace gas 2 accumulation in the atmosphere or the destruction of stratospheric ozone, not to speak of global radioactive contamination. GAIA will probably prevail as a living system but it probably does not give much importance to man's survival as such, and it is man that has to take care of his own survival. In the ecosystem of Planet Earth, soils are the thin interface between lithosphere and atmosphere which constitutes the essential substrate for the terrestrial biosphere, the productivity of which far exceeds that of the oceans, even though the latter cover a much larger area than the continents. Soils themselves are complex systems. They develop through weathering of minerals, are colonised by living organisms which in turn modify their substrate making it suitable for other organisms. This induces a primary ecological succession which eventually reaches a climax, in equilibrium between climate, soil and the biological communities.

In the extensive field of earth sciences, with its many subdisciplines, the trans fer of knowledge is primarily established via personal communication, during meetings, by reading journal articles, or by consulting books. Because more information is available than can be assimilated, it is necessary for the individual to search selectively. Books take more time from the inception of an idea until publication than any of the other means of communication men tioned. As a consequence, their function is somewhat different. Many good books are a compilation of up to date knowledge and serve as reference or instruction manuals. Some books are a collection of previously published papers dealing with a certain topic, while others may basically provide large sets of data or examples. The Frontiers in Sedimentary Geology series was established both for stu dents and practicing earth scientists who wish to either stay abreast of the most recent ideas or developments or to become familiar with an important topic in the field of sedimentary geology. The series attempts to deal with sub jects that are in the forefront of both scientific and economic interest. The treatment of a subject in an individual volume should be a combination of topi cal, regional, and interdisciplinary approaches. Although these three terms can be defined separately, in reality they should flow into each other. A topical treatment should relate to a major category of sedimentary geology.

The zone where land and sea meet is composed of a variety of complex environments. The coastal areas of the world contain a large percentage of its population and are therefore of extreme economic importance. Industrial, residential, and recreational developments, as well as large urban complexes, occupy much of the coastal margin of most highly developed countries. Undoubtedly future expansion in many undeveloped maritime countries will also be concentrated on coastal areas. Accompanying our occupation of coasts in this age of technology is a dependence on coastal environments for transportation, food, water, defense, and recreation. In order to utilize the coastal zone to its capacity, and yet not plunder its resources, we must have extensive knowledge of the complex environments contained along the coasts. The many environments within the coastal zone include bays, estuaries, deltas, marshes, dunes, and beaches. A tremendously broad range of conditions is represented by these environments. Salinity may range from essentially fresh water in estuaries, such as along the east coast of the United States, to extreme hypersaline lagoons, such as Laguna Madre in Texas. Coastal environments may be in excess of a hundred meters deep (fjords) or may extend several meters above sea level in the form of dunes. Some coastal environments are well protected and are not subjected to high physical energy except for occasional storms, whereas beaches and tidal inlets are continuously modified by waves and currents.

The ihsan Ketin NATO Advanced Study Institute on the Tectonic Evolution of the Tethyan Region was conceived in 1982 in Veszprem, Hungary, when three of the organizers (B. C. B. , L. H. R. and A. M. C. 9. ) had come together for a meeting on the tectonics of the Pannonian basin. All three of us had experience in the Tethyan belt and all three of us had been for some time deploring the lack of communication among workers of this immense orogenic belt. Much new work had been completed in such previously little-known areas as Turkey, Iran, Afghanistan, the People's Republic of China, the entire Himalayan region, as well as new work in the European parts of the chain. Also, ironically, parts of the belt had just been closed to field work for political reasons, so it seemed as if the time was right to sit back and consider what had been done so far. Because the Istanbul group had had an interest in the whole of the Tethyan belt and because that ancient city was more centrally locElted with excellent opportunities to see both Palaeo- and Neo-Tethyan rocks in a weekend excursion, we thought that Istanbul was a natural place for such a meeting, not mentioning its own considerable attractions for the would-be contributors. A happy coincidence was that Prof.