Fossil collecting is a fascinating hobby which has grown considerably in popularity over the last few decades. Its appeal is understandable; it combines the excitement of discovery with the practical skills of collecting and preparing specimens, and the academic challenge of identifying fossil finds. There are few other branches of science in which a beginner can make a serious contribution to the knowledge of our planet’s remarkable prehistory

The Earth is more than four billion years old. Its history is documented by the rocks that form the Earth’s crust, which lies beneath our feet and can be structurally complex in some places. The time that has elapsed since the formation of our planet is infinitely long when compared to the age of the human lineage, and several methods make it possible for us to measure geological time. The study of fossils—the remains of animals and plants preserved in sedimentary rocks—allows us to recognize the order of events that have formed the Earth.

A work of this nature depends very heavily on one's fellow workers. We take this opportunity to thank those many people who have assisted us with advice, facilities, the loan of specimens, and helpful discussions over many years. We apologize to anyone who may have inadvertently been missed here. We especially would like to mention staff of the Natural History Museum, Dr С Patterson, Dr A. Milner, Dr M. K. Howarth, Dr P. D. Taylor, Dr A. Smith, Dr N. J. Morris and Mr R. J. Cleevely for allowing us to examine specimens in their care. Also, many thanks go to Dr B. M. Cox (British Geological Survey) and Dr J. K. Wright (Royal Holloway and Bedford College) for allowing us to use photographs. Professor J. H. Callomon (University College, London), Dr G. Chancellor (Peterborough City Museum), Mr Alan Dawn (Stamford), Dr D. T. Donovan (University College, London), Dr Tim Palmer (University of Wales at Aberystwyth), Dr Mike Barker (Portsmouth Polytechnic), Ms Liz Harper (Open University), Dr F. T. Fursich (University of Wurtzburg), and Dr R. G. Clements, Dr J. W. Faithfull and Mr R. Branson (Leicester University) all offered helpful advice. At Leicester Museum Dr M. A. Taylor and Dr A. Cruickshank offered helpful discussions on aspects of marine reptile paleobiology. We have also drawn heavily on data from Dr A. Williams and Dr I. St. J. Fisher, both of whom have made important contributions to our knowledge of the geochemistry of the Oxford Clay. Ms S. Button, Mr J. Taylor and Mr A. Lloyd assisted with diagrams. Mrs D. Туе and Mrs W. D. Hebden helped type manuscripts. Dr Alistair Crame (British Antarctic Survey) and Dr Ed. Jarzembowski acted on behalf of the Palaeontological Association.

With the decision to produce this guide book we very rapidly found that specimens of many of the fossils were not represented in our collections. To remedy this we undertook several field visits to enrich the collections at Leicester University and the Open University. We therefore thank the London Brick Company for permission to visit their brick pits, and in particular thank Mr P. Furr (LBC Bletchley), Mr Keith Morton (LBC Stewartby) and Mr A. Robinson (LBC Calvert) for their help.

It is easier to give examples of geological structures than to define them. The word 'structure' means 'that which is built or constructed'. Structural geologists use the word to signify something that has been produced by deformation; that is, by the action of forces on and within the Earth's crust. Structures consist of a geometric arrangement - of planes, lines, surfaces, rock bodies, etc. The form and orientation of this arrangement reflect the interaction between the deforming forces and the preexisting rock body. <...>