STRUCTURE OF THE VOLUME AND TERMINOLOGY USED This book contains scientific descriptions of 63 localities (Figure A) of at least national importance for Quaternary geology, geomorphology and environmental change in South-West England. These sites were selected by the Geological Conservation Review and are accordingly designated 'GCR' sites. Chapter 1 provides an introduction to the Quaternary. Chapter 2 synthesizes the geomorphological development and Quaternary history of the region, and outlines the principles involved in site selection. The individual GCR site descriptions form the core of the book. In the following chapters, sites are arranged and described in broad geographic areas and by research topic. This is necessitated by the widely disparate nature of the field evidence in Soutb West England: sites demonstrating the full range of Quaternary and geomorphological features are not evenly and conveniently dispersed throughout the region, and some areas have significant gaps. Neither do the individual chapters contain sites that neces sarily equate with particular site selection networks. Rather, the chosen chapter headings provide the least repetitive means of describing the sites and background material. Where possible, a chronological approach, from oldest to youngest, has been used to describe sites within a given chapter. Again, this approach is not always possi ble, and a group of sites may show variations on landform or Stratigraphie evidence broadly within one major time interval or chronostratigraphic stage; inevitably there are many overlaps.

STRUCTURE OF THE VOLUME AND TERMINOLOGY USED This book contains scientific descriptions of 63 localities (Figure A) of at least national importance for Quaternary geology, geomorphology and environmental change in South-West England. These sites were selected by the Geological Conservation Review and are accordingly designated 'GCR' sites. Chapter 1 provides an introduction to the Quaternary. Chapter 2 synthesizes the geomorphological development and Quaternary history of the region, and outlines the principles involved in site selection. The individual GCR site descriptions form the core of the book. In the following chapters, sites are arranged and described in broad geographic areas and by research topic. This is necessitated by the widely disparate nature of the field evidence in Soutb West England: sites demonstrating the full range of Quaternary and geomorphological features are not evenly and conveniently dispersed throughout the region, and some areas have significant gaps. Neither do the individual chapters contain sites that neces sarily equate with particular site selection networks. Rather, the chosen chapter headings provide the least repetitive means of describing the sites and background material. Where possible, a chronological approach, from oldest to youngest, has been used to describe sites within a given chapter. Again, this approach is not always possi ble, and a group of sites may show variations on landform or Stratigraphie evidence broadly within one major time interval or chronostratigraphic stage; inevitably there are many overlaps.

This volume illustrates some of the significant aspects of magmatic activity from Devonian (408 million years ago) to early Permian (270 million years ago) times in SW England. This period covers the progressive development of the Variscan mountain-building episode, from initial basin formation to final deformation and the subsequent development of a fold mountain belt - the Variscan Orogen. Both extrusive (volcanic) and intrusive (plutonic) rocks are found in the orogen, and chart the various stages of its magmatic development. The sites described in this volume are key localities selected for conservation because they are representative of the magmatic history of the orogen from initiation to stabilization. Some of the earliest volcanic activity in the Devonian is represented by submarine basaltic and rhyolitic lavas developed in subsiding basins, caused by the attenuation of the existing continental crust. In some cases, extensive rifting and attendant magmatism produced narrow zones of true oceanic crust, whereas elsewhere basaltic volcanism is related to fractures in the continental crust at the margins of the basins. After the filling of the sedimentary basins, and their deformation caused by crustal shortening (late Carboniferous Period), further activity is manifested by the emplacement of the Cornubian granites and later minor basaltic volcanism in the early Permian. Accounts of the constituent parts of this history have enriched geological literature from the nineteenth century onwards, and have contributed to the advancement and understanding of magmatic and tectonic processes.

Recent developments in Pleistocene research have prompted the authors to produce this up-to-date, concise account of environmental changes during the past two million years. Well-illustrated and referenced, it possesses a unique position in the literature on Pleistocene events in the British Isles.