Advances in Military Geosciences

Edward P. F. Rose Editor German Military Geology and of the British During World War II Advances in Military Geosciences

Series Editors Peter Doyle London South Bank University, London, United Kingdom Judy Ehlen Haytor, Devon, United Kingdom Francis Galgano G67 Mendel Science Center, Villanova University, Villanova, PA, USA Russell Harmon North Carolina State University, Raleigh, NC, USA Edward P. F. Rose Royal Holloway, University of London, Egham, Surrey, United Kingdom Advances in Military Geosciences is a book series which explores the interaction between current and historic military operations and earth science, including geography, geology, geophysics, soil science, ecology, hydrology, glaciology and atmospheric sciences. Military activities are almost always strongly integrated within a wide spectrum of geoscience. The decisive outcomes of land battles throughout history have been dictated in large part by the terrain and environmental setting. Modern military operations rely on a wide range of land-, air-, sea-, and space-borne intelligence and knowledge of dynamic terrain processes and conditions. In addition, the study of geo-based environmental science is critical to both the sustainable management of military reservations and installations, as well as the evaluation of how terrain and environmental conditions may impact military equipment and operations. Advances in Military Geosciences contains single and multi-authored books as well as edited volumes. Series Editors are currently accepting proposals, forms for which can be obtained from the publisher, Zachary Romano (Zachary.Romano@ springer.com).

More information about this series at http://www.springer.com/series/15030 Edward P. F. Rose Editor

German Military Geology and Fortification of the British Channel Islands During World War II Editor Edward P. F. Rose Department of Earth Sciences Royal Holloway, University of London Egham, Surrey, UK

ISSN 2522-8315 ISSN 2522-8323 (electronic) Advances in Military Geosciences ISBN 978-3-319-22767-2 ISBN 978-3-319-22768-9 (eBook) https://doi.org/10.1007/978-3-319-22768-9

© Springer Nature Switzerland AG 2020 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

This Springer imprint is published by the registered company Springer Nature Switzerland AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland Preface

Major advances in military geosciences were stimulated by the two world wars. That is especially true for German armed forces during World War II, who made military use of some 400 geologists: by far the largest number by any nation in wartime, ever. However, the lessons learnt are largely concealed in unpublished reports now dispersed in archives within the UK and the USA as well as Germany, and these reports are easily readable only by people with some understanding of the German language as well as geology. This book brings together information from the disparate sources to provide a case history in English. It illustrates the kind of geoscientists that German forces used as ‘military geologists’, and what could be expected of them in wartime. In doing so, it focuses on a unique region: the Channel Islands—the only part of the British Isles to be occupied by German forces during World War II. After the war and until the end of the twentieth century, it was generally believed that only two German geologists had served on the Islands, and that all their reports had been destroyed prior to the final surrender. However, this book demonstrates that this was a misconception: at least 14 men in total are now known to have been used on the Channel Islands to provide professional expertise as geologists within the German armed forces, and over 50 of their reports have survived within Germany, the USA, and the UK. For the UK and France, the war had begun on 3 September 1939. Germany had invaded Poland on 1 September, and when its Führer Adolf Hitler rejected an ulti- matum by the British and French governments demanding that the invading troops be withdrawn, they declared war. A British Expeditionary Force began moving to France on 4 September, to take up positions in the NE: a defensive line to guard against German attack through neutral Belgium. During the months of the ‘Phoney War’ that followed, the opposing sides built up their military might. The attack finally came on 10 May 1940. Despite spirited resistance, the British Expeditionary Force was driven back to the Channel coast and, between 27 May and 4 June, mostly evacuated from the vicinity of the port of Dunkirk. French and remaining British troops fought on until German victory in the Battle of France was conceded, and the French government was compelled to sign an armistice with that of Germany on 22

v vi Preface

June. Deemed indefensible in the face of overwhelming German might, the Channel Islands, close to the Normandy coast of France, were demilitarized and partly evac- uated. German troops took possession of undefended on 30th June, on 1st July, and on 2nd July 1940. As explained in Chap. 1 of this book, German forces had thereby seized an area of great scenic beauty, whose long history had led to the development of a unique island culture. Although English was the local language, the Islands were not legally part of England or indeed the UK. Originally part of the ancient Duchy of Normandy, then as now they had their own distinctive systems of government, issued their own Sterling banknotes, and issued their own postage stamps—governance, currency, and postage differing even between the major islands. German forces had to control both people and terrain of a distinctive character—and had access to a considerable legacy of constructed by the British in earlier centuries, intended to provide protection from potential invasion by the French. The rocks that are an obvious feature along most of the island coasts are similar to those that may be seen in nearby France, in Normandy and Brittany. They are mostly of great age, some formed at least 2000 million years Before Present, and many associated with a period of mountain building (the ‘Cadomian Orogeny’) that took place some 600 million years Before Present, for which evidence is found nowhere else in the British Isles. The British Geological Survey has therefore described the Channel Islands amongst its ‘classical areas of British geology’. Chapter 2 describes the long history of geological studies on the Islands that culmi- nated in a considerable pool of knowledge available to German forces when they began their period of occupation. Although the early months of occupation were relatively uneventful, the situa- tion changed from March 1941 onwards, as German aggressive might became focused against the Soviet Union. In June 1941, Hitler decreed that the Channel Island garrison was to be increased to a full division, to counter any potential attempt by the British to recapture the Islands whilst his main forces attacked eastwards. Moreover, he issued two programmes for the Islands’ fortification, one to last 14 months, the other 7 years. Later that year, on 20 October, he issued a directive that permanent fortification should be pressed forward energetically, to create an impregnable fortress. His intention was that the Islands would forever remain a fortified outpost of the German state, much as Gibraltar, a rocky peninsula jutting south from Spain at the western entrance to the Mediterranean Sea, then was for the UK. On 15 December, this was followed by a construction order for the Atlantic Wall: intermittent coastal fortifications that stretched from Norway in the north to the border of France with Spain in the south, to create a defensive western boundary for German-occupied Europe, including the Channel Islands. Chapter 3 describes how German armed forces were organized to apply their considerable engineering and geological skills to this formidable task. The geology of the Islands had an important bearing on fortification. Geological history had been a formative influence on Island surface features, and these in turn influenced the selection of many military construction sites. The best sources for quarrying construction materials, such as crushed stone for making concrete and Preface vii sand for cement, were determined by geologists. Geologists also advised on where best to site wells or infiltration galleries to make use of groundwater for secure water supplies—at a time of unusually low rainfall. German armed forces made operational use of far more military geologists during World War II than their British and American opponents worldwide. Indeed, although between 1941 and 1943 the German Army and the German Air Force in total made use of at least 14 uniformed geologists on the Channel Islands, during this period the British Army made use of only three military geologist staff officers in total, in all of its theatres of operation. Records of German geological activity were amongst the military documents systematically destroyed prior to surrender of the Islands at the end of the war, on 9 May 1945. However, duplicate copies of geological reports, many illustrated by thematic maps, have been discovered in recent years within archives outside the Islands. These reveal the names of the geologists involved and the nature of their work. Chapters 4 and 5 describe and illustrate how the work of military geologists from the Army and Air Force, respectively, contributed to the fortification pro- gramme on Jersey, Chaps. 6 and 7 rather differently to fortification on Guernsey, and Chap. 8 to fortification on Alderney. One of the legacies of this geological work was a detailed record of groundwater conditions on the Islands during the occupation, especially for the year 1942. Nothing like this had been attempted on the Islands during the previous centuries, nor had it been attempted in such detail in other ‘hard rock’ areas of the British Isles as a whole. As explained in Chap. 9, the German studies have provided benchmark infor- mation that may be used, together with information gathered during postwar studies by the British Geological Survey, to generate a relatively long-term understanding of groundwater conditions on the Islands—essential for forward planning of adequate water supplies as the Islands are further developed as a popular holiday resort, and the world faces challenges of climate change and changing rainfall patterns. In conclusion, Chap. 10 sets the German military geological work on the Channel Islands in a broader context. It briefly describes similar Atlantic Wall fortifications on the Normandy coast nearby, fortifications that, unlike those on the Islands, were bombarded and many of them extensively damaged prior to or during the Allied invasion that began on D-Day, 6 June 1944. Since Alderney has long been known as the ‘Gibraltar of the Channel’, it compares and contrasts Channel Island fortifica- tion with coeval British fortification of Gibraltar, especially with regard to the use of geology and geologists to facilitate military construction works. It briefly reviews the wartime use of military geologists by the British Army, as individual staff offi- cers in field force general headquarters, from 1940 within a team formed by the South African Engineer Corps, and from 1943 in two teams for terrain analysis remote from operational areas, one in England and the other in India. Finally, it describes wartime use of geologists in the United States Army, as a Military Geology Unit of the US Geological Survey, its many members primarily although not exclu- sively located near Washington DC. However, although the US Army made more extensive use of military geologists than the British Army, their numbers were again small relative those serving with German armed forces: less than 100 actual geolo- gists by the war’s end. viii Preface

A legacy of German engineering work as a whole is the range of fortifications that still exist on the Islands. The Allied landings in Normandy that began on D-Day bypassed the Channel Islands. The Islands and their fortifications were finally sur- rendered at the end of the war, untested and intact. Much of the metalwork was soon removed in postwar years for recycling, but the concrete structures mostly remain, and representatives of the many types have now been conserved, sometimes refur- bished, to serve as tourist attractions. Some of those attractions are now housed in wartime underground facilities originally designed to provide accommodation and storage safe from aerial or naval bombardment. Almost all the sites illustrated in this book may freely be viewed from the outside, if only from a distance, but many sites are open, at least periodically, to paying visitors: a remarkably compact and acces- sible testimony to the programme of intense fortification, for which details of admission are now readily available online. The book thus complements the many other books that describe the German occupation of the Channel Islands from the perspective of the people involved, either the British islanders or the German occupiers, or by reference to military events or military engineering works. It is an account, written by professional geol- ogists of different but very relevant expertise, that focuses on geology and geolo- gists and on their importance to the construction of this unique, supposedly impregnable, fortress. Published in 2020 to help mark both the 80th anniversary of the start of the German occupation and the 75th anniversary of its end, it is hoped that the book will be of interest not only to geoscientists in general but also to the residents of the Channel Islands, in helping them to understand factors that influenced the construc- tion of some of the fortifications now mellowing into the natural landscape; to peo- ple interested in the history of World War II, whether from the German or Allied side, because of the special significance of this ‘impregnable fortress’; and to the many tourists that visit the Islands, to enjoy their unique culture, mild climate, sandy beaches, marine wildlife, long history, fine cuisine—and over 800 years of defensive fortification that peaked during the German occupation. The book draws on contemporary German records now preserved in the archives of the British Geological Survey at Keyworth, near Nottingham, in the UK; the Military Division of the Federal German Archives (Bundesarchiv-Militärarchiv) at Freiburg-im-Breisgau, Germany; the archives at the Geoinformation Centre of the modern German Army (Bundeswehr Geoinformationen Zentrum) at Euskirchen, Germany; and the National Archives and Records Administration at College Park, Maryland, in the USA. As indicated in the text, its core chapters bring together and significantly amplify data that the editor has published, frequently in co-authorship with Dierk Willig, in issues of the Channel Islands Occupation Review and else- where, between 2002 and 2014. Footnotes are used to explain geological terms not in common use and to indicate information sources not listed in the references that end each chapter. They are also used to indicate details of German nomenclature and documents that are ­unnecessary for the general reader but which provide the data required by more serious scholars. Preface ix

Permission to reproduce some of this material is indicated where appropriate in the captions to individual figures, and so gratefully acknowledged. The chapter authors also acknowledge the kind assistance and encouragement that they have received over many years from members of both the Jersey and Guernsey branches of the now well-established and currently very active Channel Islands Occupation Society, particularly the late Michael Ginns, and the Society’s ‘Review’ editors Matthew Costard, Trevor Davenport, and Paul and Iain Ronane. John Renouf kindly read drafts of Chaps. 4 and 5 for Jersey, Pierre Renier Chaps. 6 and 7 for Guernsey, and Trevor Davenport Chap. 8 for Alderney, but any remaining errors are the responsibility of the sole author in each case. Wendy Cawthorne, Assistant Librarian at the Geological Society of London, was particularly helpful in gaining access in England to some of the more obscure bibliographic references and biographical information, and Professor Hermann Häusler of the University of Vienna helpful in providing such information from sources in Austria and Germany. Grateful thanks are due to all of these kind colleagues. My co-authors have read chapters in this book additional to their own and made helpfully constructive com- ments; the Springer editors have guided preparation of the book in its earliest and final stages; but the final responsibility for any errors or omissions remains entirely my own.

Egham, UK Edward P. F. Rose Contents

1 Introduction ���������������������������������������������������������������������������������������������� 1 Edward P. F. Rose and John T. Renouf 2 Geology ������������������������������������������������������������������������������������������������������ 25 John T. Renouf and Edward P. F. Rose 3 Geologists and the German Armed Forces �������������������������������������������� 81 Edward P. F. Rose and Dierk Willig 4 Jersey and the German Army ���������������������������������������������������������������� 107 Edward P. F. Rose 5 Jersey and the German Air Force ���������������������������������������������������������� 163 Edward P. F. Rose 6 Guernsey and the German Army ���������������������������������������������������������� 199 Edward P. F. Rose 7 Guernsey and the German Air Force ���������������������������������������������������� 255 Edward P. F. Rose 8 Alderney ���������������������������������������������������������������������������������������������������� 289 Edward P. F. Rose 9 Groundwater Investigations: German and British ������������������������������ 335 Nicholas S. Robins 10 Conclusion: Contemporary Context and Postwar Legacy ������������������ 357 Edward P. F. Rose

Index ������������������������������������������������������������������������������������������������������������������ 395

xi About the Contributors

John T. Renouf Born on Jersey, John Renouf began research studies in the University of London by a PhD thesis on the older rocks of western Brittany in France. During a subsequent Jersey-based career, first at the Jersey Museum and subsequently to retirement at the Department of Education, his research interests widened to take in Channel Islands’ geology as it can be used to enhance archaeo- logical and historical work and, particularly, to more recent geology in the islands and the significance of past sea levels above and below that of the present.

Nicholas S. Robins Nick Robins is a graduate of the University of Southampton, but his degrees include an MSc in hydrogeology and a DSc, both from the University of Birmingham. He is author or co-author of over 100 technical papers and articles concerning aspects of hydrogeology of the UK, the Channel Islands, and elsewhere, notably Sub-Saharan Africa and the Caribbean; he is also author/editor of nine books on a variety of hydrogeological topics. Now working part-time as a hydroge- ologist, on retirement from the British Geological Survey, his other recent activities include the role of Editor-in-Chief for the two book series published by the International Association of Hydrogeologists.

Edward P. F. Rose Ted Rose graduated from Oxford University with a ‘first’ in geology and a doctorate for a thesis on Libyan echinoid palaeontology and Cenozoic stratigraphy, before lecturing on geology at London University: at Bedford College from 1966, at Royal Holloway from 1985 until retirement from a senior lectureship to an honorary research fellowship in 2003. Commissioned into the Territorial Army in 1962 via the Oxford University Officers Training Corps, he served from 1969 to 1990 as a military geologist (from 1974 senior military geologist) in the (Volunteers), from 1987 to 1990 in the rank of colonel. He is author or co-author of over 120 book chapters or journal articles on the history of military applications of geology (additional to publications on echinoid palaeontology and the geology of Gibraltar); he received the Sue Tyler Friedman Medal of the Geological Society of London in 2014.

xiii xiv About the Contributors

Dierk Willig Dierk Willig graduated from the University of Würzburg (Dr. rer. nat.) for a thesis on the history of military applications of geology. He has developed a career as a civilian military geologist within the modern German Army and also a strong record of publication on topics relating to historical aspects of military geol- ogy. He leads the Geology/Hydrology/Geophysics Division at the Bundeswehr Geoinformation Centre of the German Army and holds the reserve army rank of lieutenant colonel. Chapter 1 Introduction

Edward P. F. Rose and John T. Renouf

Abstract The Channel Islands, British since 1204, lie close to the Normandy coast of northern France. They have a temperate marine climate and rural rather than urban landscapes with many features attractive to tourists. The largest islands (Jersey, Guernsey, Alderney and ) are fringed with spectacular coastal scenery and dotted with sites of prehistoric or historic interest, the latter principally fortifications to deter invasion. A small Roman fort on Alderney, probably constructed in the fourth century AD, is the earliest of these to be stone-built. British fortification to deter invasion from France began with the construction of castles on Jersey and Guernsey between the thirteenth and seventeenth centuries. It continued during the seventeenth to early nine- teenth centuries with the development of coastal for batteries of artillery and towers to be defended by small arms or cannon fire. It culminated in a massive pro- gramme of perimeter forts constructed on Alderney during the mid nineteenth cen- tury: part of arguably the greatest programme of national fortification in the British Isles. All of these fortifications, being massive in construction and strategic in their position, were to varying degrees adapted by German forces after their seizure of the islands in the summer of 1940, to help counter potential recapture by the British.

1.1 Regional Setting

The Channel Islands are British Crown Dependencies situated in the south of the English Channel, over 100 km from England and some 25 to 50 km from the Normandy coast of France (Fig. 1.1). Seven islands are permanently inhabited: the

E. P. F. Rose (*) Department of Earth Sciences, Royal Holloway, University of London, Egham, Surrey, UK e-mail: [email protected] J. T. Renouf Le Cotil des Pelles, La Route du Petit Port, St. Brelade, Jersey e-mail: [email protected]

© Springer Nature Switzerland AG 2020 1 E. P. F. Rose (ed.), German Military Geology and Fortification of the British Channel Islands During World War II, Advances in Military Geosciences, https://doi.org/10.1007/978-3-319-22768-9_1 2 E. P. F. Rose and J. T. Renouf

Fig. 1.1 Location of the largest Channel Islands relative to England and France

principal islands of Jersey (118 km2), Guernsey (65 km2), Alderney (8 km2) and Sark (5 km2), and the lesser islands of (2 km2), (0.3 km2) and (0.2 km2). Total resident population is currently about 166,000, of whom most (about 105,000 people) live on the largest island, Jersey, and of these about 33,500 in its main town, St. Helier.1 In 1939, before the start of World War II, there were only about 50,000 people on Jersey, 40,000 on Guernsey, 1500 on Alderney and 600 on Sark (Cruickshank 1975). There are also adjacent , rocks and reefs that are normally uninhabited: the , Écréhous, Dirouilles and the Paternosters near Jersey; Caquorobert, Crevichon, Grande Amfroque, Les Houmets and near Guernsey; and , the Casquets, and Renonquet near Alderney. Characteristic features of Channel Island geography, history and culture have been extensively described in many earlier books (e.g. Coysh 1977), so much infor-

1 www.gov.je/Leisure/Jersey/pages/profile.aspx, last accessed 12 January 2019. 1 Introduction 3 mation is widely available. Notably, Channel Island laws and administrative sys- tems are distinct from those of England, and therefore the United Kingdom as a whole, having been independently derived from the medieval Duchy of Normandy. Although English is the local language, a few older inhabitants still converse in a Norman French patois. The islands are divided into two almost wholly self-governing bailiwicks:2 Jersey and Guernsey, each including its own offshore reefs but with the also embracing Alderney and Sark. The last two islands have a measure of self-government but ultimately defer to Guernsey. The main islands issue their own postage stamps, banknotes and coinage (both notes and coinage being inter- changeable locally with British currency). The economy is traditionally agricul- tural, noted both for dairy cattle and products and for the growing of vegetables. Tourism has always been important and continues to be so but has been overtaken by banking and finance. The warmest and sunniest of the British Isles, the geogra- phy and history of the Channel Islands have given them a unique character. When, after the defeat of France and its allies early in World War II, German forces began their occupation of the islands in the summer of 1940, they found that they had arrived in a region very different to their own home country. Both the islands and their 1940–45 German occupation have given rise to an extensive litera- ture: Gardiner (1998) provides a comprehensive list of publications up to almost the end of the twentieth century, and more have been published subsequently.

1.2 Geography: The Physical Background

As will be described in Chap. 2, it has long been recognized that all of the islands are formed by bedrock that is very old and very strong, and more closely similar to the rocks that can be found nearby in northern France than across the Channel in England. The islands themselves contain no bedrock younger than the Cambro– Ordovician, although rocks formed in the vast 450-million-year time interval since then are well represented in adjacent France. The low dissected plateaux that char- acterize the islands’ surface are erosional outliers of an ancient peneplain that begins at the coast of Normandy (Jee 1982; Renouf 1993). Jersey’s main plateau forms a major feature of its land surface. It slopes gently down (from a height that averages about 100 m above sea level along the north coast) to a height of some 60 to 50 m along the south coast, where abrupt steep slopes descend to the sea (Fig. 1.2). A series of major, deeply incised valleys, prin- cipally eroded by more or less north to south flowing rivers, is now occupied by

2 Bailiwick: the district or jurisdiction of an official known as a bailie or bailiff. In the Channel Islands, each of the two bailiwicks has a lieutenant-governor appointed by and representing the British Crown, and a bailiff who is the bailiwick’s most important citizen: traditionally the presid- ing officer of its local government (the States, to which members are elected) and the head of its judiciary. 4 E. P. F. Rose and J. T. Renouf

Fig. 1.2 Map of Jersey showing major features of relief. Modified by J.T. Renouf from a hachured map created by N.L.V. Rybot in the 1930s small streams. Etched into the steep coastal cliffs and the gently sloping plateau above are what may be termed a staircase of flatter, bench-like breaks of slope, all of which may represent erosion reflecting a complex story of interplay between climatic and tectonic events and associated sea-level changes over the last several million years (Jones et al. 1990; Renouf and James 2010). Jersey’s shape is strongly influenced by geology. The NW, SW and SE corners of the island are formed by granite masses that are highly resistant to erosion. In con- trast, the NE corner is formed of conglomerate: a sedimentary rock that is more easily eroded. The major embayments that are a feature of the western and southern coasts have been formed by erosion of the slightly metamorphosed, fractured and cleaved (and so relatively weak) Precambrian sedimentary rocks that otherwise form much of the island (Fig. 1.2). The high and steep cliffs that form the northern coast are, apart from the NW granite, eroded into a great variety of variably resistant igneous rocks, many of volcanic origin. Guernsey is less regular in outline than Jersey and is overall triangular rather than rectangular in shape (Fig. 1.1). The main plateau area occupies the base of the ­triangle in the south (where the coastal cliffs are steepest) and, in contrast to Jersey, slopes from south to north. However, its average height is similar. It declines from a maximum of about 100 m above sea level in the SE to end at a steep inland scarp, trending approximately west-east, that descends to the narrowing northern sector of the island: a region of much lower and more varied relief. No geological formation 1 Introduction 5 has been dominant in controlling the pattern of erosion and coastal embayments are the result of complex processes. However, the low-lying northern part of Guernsey has been significantly shaped by the effects of climate and sea-level changes during Quaternary time. Indeed, a major part of northern Guernsey was for a time a sepa- rate island, until the intervening strait was reclaimed from the sea in the 1800s. The small island of Sark, to the east of Guernsey (Fig. 1.1), is the most plateau-­ like of all the Channel Islands. It has an essentially flat surface at about 100 m in height, and is surrounded on all sides by steep to vertical cliffs. Alderney is also an inclined cliff-bounded plateau, but facing east (Figs 1.1 and 1.3). Much of the eastern lowland area is underlain by sandstone similar in age of formation to the conglomerate on Jersey, and similar in its response to erosion. High tidal ranges, between 6 and 14 m, are a feature of the coasts within the Normanno-Breton Gulf area in which the Channel Islands are situated (cf. Fig. 1.1). In consequence, extensive rocky wave-cut platforms or wide sandy beaches are exposed in many areas at low tide, but submerged at high tide level.

Fig. 1.3 Aerial view of Alderney, from 5000 ft (about 1500 m), showing the steep cliffs fringing the SW coast to the right of the image; the main town (St. Anne) in the centre; and the gentle regional downward slope of the surface plateau towards the major harbour of Braye Bay (partly enclosed by a nineteenth century breakwater) and the NE lowland of the island (top left of image). From an original print by Richards of Alderney, and reproduced by kind permission 6 E. P. F. Rose and J. T. Renouf

Climate is temperate maritime, lacking marked variations or extremes.3 At lati- tude 50 deg north, the islands lie essentially within the mild westerly airflow that typically separates the sub-tropical high-pressure zone to the south and the more northerly course of Atlantic low pressure systems. Sheltered to some extent by the much greater landmasses of England to the north and France to the south and east, the islands escape the worst of the winds often associated with offshore locations. The climate is thus typified by mild damp cloudy winters and warm drier sunnier summers. Jersey averages a mean daily air temperature of 11.5 °C, experiences ground frosts on only 60 days per year and has snow or sleet on only 12 days per year. The average long-term annual rainfall is 877 mm on Jersey and 790 mm on Guernsey, but actual annual rainfall may vary considerably from the long-term mean (see Chap. 9). The bedrock of the largest islands is covered by a variable thickness of loess: a wind-blown silt deposited during late Quaternary time (and so comparable with the ‘brick earth’ known from southern England and the ‘limon des plâteaux’ of northern France). Climate and this geological stratum in particular have together generated fertile soils (Jee 1982), as described for Jersey in particular by Jones et al. (1990). The islands are still predominantly rural, as they were in 1940, with intensively worked arable land and grassland used for dairy farming, plus small areas of heath- land, semi-natural mixed deciduous woodland, and wetland. Palaeobotanical records reveal that, from about 10,000 years ago, periglacial tundra was succeeded by a vegetation mosaic in which woodland was important, its composition varying with changes in climate and sea level until reaching a fully temperate vegetation cover by about 8000 years before present. Not surprisingly, given its close proxim- ity, the present biota has closest affinity with neighbouring France. Apart from birds, the native fauna is relatively restricted in variety, with few mammals or larger reptiles, although the islands host the most northerly occurrence of some southern European plants and contain some unique subspecies of small mammals.

1.3 Archaeology and History

Each of the islands would have been accessible to ancient humans at times during the last million years from what is now France without the use of boats: when sea level was low because of cyclic climate (Jones et al. 1990; Sebire 2011; Renouf 2015). Oldest habitation is currently known from Jersey, from a Palaeolithic (Old Stone Age) cave shelter at La Cotte de St. Brelade. Fossil remains and human arte- facts from this well documented archaeological site have been dated to between 250,000 and 50,000 years before present and ascribed to habitation by Neanderthals (Homo neanderthalensis).

3 www.metoffice.gov.gg/climate.htm last accessed 11 January 2019. 1 Introduction 7

The first modern humans (Homo sapiens), associated with a Magdalenian cul- ture, are also currently known only from Jersey. Evidence of their presence has been dated to about 14,000 years before present, a time following the end of the extremely cold climate of the Last Glacial Maximum. Following the end of the last Pleistocene glacial period (and so of the Quaternary ‘Ice Age’) at about 11,000 years before present, the subsequent post-glacial warming led to rising sea levels and so progres- sive flooding of the former cold climate landscape. Each of the islands in turn became isolated by the sea from the adjacent Normandy coast and nearby islands. Temperate climates prevailed over the whole Normanno-Breton Gulf area by about 9000 years before present and there is evidence for Mesolithic habitation on the islands then, followed by extensive occupation by Neolithic farming communities from about 8000 years ago. It was these Neolithic peoples who exploited the geological resources of the islands to a significantly greater extent, using stone for domestic purposes (fashioning it into axes, mullers for grinding cereals, and ornaments) and construct- ing passage graves and other massive stone (megalithic) monuments. Trade beyond the islands became increasingly important from the Neolithic onwards, but this was trade based initially within the prevailing societies of NW France—of which the island communities were an integral part—and only later to areas further away, such as southern England across the Channel. Towards the close of the Iron Age, during the first century before the Christian era, the Celtic tribes of France (then known as Gaul) became subject to Roman conquest. Thereafter, for almost four centuries, Gaul—including its NW area near the Channel Islands, given the Celtic-derived name of Armorica by the Romans—became increasingly Romanized, and its culture consequently Gallo-Roman. Cross Channel trading was important in the Roman empire, which included England (Britannia) from the first century of the Christian era. The final collapse of the Gallo-Roman realm in the fourth century was followed by several centuries of instability with much movement of peoples. This culminated in sea-borne raids by Norsemen (= ‘northmen’, from Scandinavia) into northern France and Armorica to the west early in the ninth century, followed later by settle- ment. In 911 Norsemen founded what became the Duchy of Normandy, named after them, and soon the Channel Islands were annexed to the Duchy and ruled by its Duke. From the conquest of England by Duke William of Normandy (who became King William I of England) in the year 1066 through to 1204, Normandy, as well as other areas of France, owed allegiance to the English monarch. However, in 1204— the most critical date in the islands’ history—King John of England was forced to cede all of Normandy except the Channel Islands to the King of France, Philippe Augustus. Thereafter the islands retained allegiance to the Crown in England and the scene was set for the islands to endure what would become six hundred years of intermittent strife with France. The military consequences of this were profound: because the islands always faced potential attack by the French, they were ­progressively fortified by the English. A few strong castles were developed on Jersey and Guernsey from the thirteenth to seventeenth centuries. More numerous and widespread redoubts and batteries appeared within the eighteenth century with 8 E. P. F. Rose and J. T. Renouf a series of coastal towers towards its end. Further coastal towers were constructed to the middle of the nineteenth century along with major forts in Jersey and Guernsey. British fortification ended with a massive programme of perimeter forts constructed on Alderney, part of arguably the greatest programme of national forti- fication in the British Isles.

1.4 British Fortification of Jersey

Jersey was to be defended by a series of British coastal fortifications constructed between the thirteenth and the nineteenth centuries (Fig. 1.4). The earliest of Jersey’s stone-built fortifications is Castle (Fig. 1.5), built on a granite promontory overlooking the wide sweep of the Royal Bay of and facing the coastline of the Cotentin, that part of Normandy from the northern tip of the Cherbourg peninsula to the port of Granville in the south (cf. Fig. 1.1). Erosion of the isolated boss of granite had produced steep slopes and high cliffs on three sides of the promontory that offered a naturally defended site. The castle was founded in the early thirteenth century and progressively strengthened thereafter to counter developments in weapon technology, and perceived threats from France. Its role as a fortress lapsed from the late sixteenth century but, between 1942 and 1944, German occupying forces developed it as a self-contained strong-

Fig. 1.4 Map of Jersey indicating sites of British-built thirteenth to nineteenth century fortifica- tions. After Rose et al. (2002) 1 Introduction 9

Fig. 1.5 Mont Orgueil Castle (cf. Fig. 1.4), viewed from the south, sited on a granite promontory and overlooking the village of Gorey at the northern end of Grouville Bay. The flat tops on the three turrets of the mediaeval castle are German concrete additions to convert the turrets to artillery fire control and observation posts (M7 on Fig. 4.3). From Wikimedia Commons, file Gorey_and_ Mount_Orgeuil_from_the_south.jpg, reproduced under the terms of the GNU Free Documentation License (CC BY-SA 3.0) point. It was adapted to provide coastal artillery fire control and observation towers, dugouts and trenches to provide shelter from bombardment of its infantry garrison, and positions for automatic and other small arms. Twenty-four ‘roll bombs’ were placed on the outer walls and a flame-thrower at the top of the steps leading to the keep. The NE were heavily reinforced to house a battle headquarters. An electricity system was installed and the water supply improved. Large rooms in the keep were converted into fully furnished barracks (Rybot 1978; Rose et al. 2002; Ford 2007). (Fig. 1.4) was built in the early fourteenth century atop granite cliffs at the NW point of Jersey. Before the invention of firearms it provided a place of refuge for the population in the west of the island, but had no secure water supply to enable it to withstand , and no resident garrison. It was easily (if briefly) captured by the French during a raid in 1373, and had fallen into ruin by the six- teenth century (Balleine 1950; Syvret and Stevens 1981). From the late sixteenth century Mont Orgueil was superseded as the principal island fortress by (Figs. 1.4 and 1.6), constructed on a granite-like (granophyre-diorite) tidal island facing Jersey’s principal port, St. Helier. With the development of cannon, Mont Orgueil was no longer a safe refuge in time of conflict, despite re-modelling of its defences. The first part of a new castle (the keep, known as the Upper Ward), adapted to contemporary fighting methods, was largely con- 10 E. P. F. Rose and J. T. Renouf

Fig. 1.6 Elizabeth Castle (cf. Fig. 1.4), sited on an igneous rock (granophyre-diorite) island facing Jersey’s main port, St. Helier. View south showing beneath the British flag the massive concrete fire control tower constructed by German forces on the castle’s keep. From Wikimedia Commons, file Elizabeth_Castle.jpg, reproduced under the terms of the Creative Commons Attribution 2.0 Generic License (Jon [CC BY 2.0 (https://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons) structed between 1594 and 1601, during the reign of the English Queen Elizabeth the First. By 1668 construction had progressively extended to form the Lower and Outer Wards. With some re-modelling, Elizabeth Castle retained a British garrison until 1923, when it was sold to the Jersey government for use as an historic monument. However, German forces returned it to its former use. In the Outer Ward, three light machine guns were installed, together with a 105 mm calibre gun protected by a bomb-proof casemate, plus other bomb-proof shelters and searchlight positions. Similar installations were constructed in the Lower Ward. The keep was in part adapted for the then modern weapons, modified to provide increased barrack accom- modation, and surmounted by a massive concrete artillery fire control tower (Partridge 1976, p. 136; Rybot 1986; Ford 2008). In the eighteenth and nineteenth centuries coastal redoubts and batteries were constructed to defend those bays and beaches deemed vulnerable to sea-borne inva- sion and, although long disused, several were adapted and re-activated by German troops. Examples are the two redoubts of Grouville Common on Jersey’s east coast: Fort William and Fort Henry (Fig. 1.4). Fort William (built originally in 1760) was strengthened with concrete emplacements and heavy machine guns. Fort Henry (an eighteenth century infantry base: Fig. 1.7) was similarly converted to a ‘resistance nest’—with two 105 mm calibre guns in concrete emplacements, two 50 mm calibre mortar emplacements connected by trenches to the fort, two light and three heavy machine guns, ten flame-throwers, one anti-aircraft gun and four searchlights, manned by an officer and 35 troops of other ranks (Ginns 1973). 1 Introduction 11

Fig. 1.7 Fort Henry (cf. Fig. 1.4), viewed from inland. In 1781 known as Fort Conway and the barracks for the 93rd Regiment of Foot, the site was re-fortified and manned by German troops during the years of occupation. From Wikimedia Commons, file Fort Henry, Jersey.jpg, repro- duced under the terms of the Creative Commons Attribution-Share Alike 3.0 Unported License (Danrok [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)], from Wikimedia Commons)

In 1778, when the French became the allies of the American Colonies in their war for independence from the United Kingdom, the governor of Jersey was certain that the French would seize the opportunity to attack the Channel Islands. He there- fore proposed the construction of 30 coastal towers to resist enemy landings (Pocock 1971; Grimsley 1988; Davies 1991)—round towers, now known as Jersey Towers, about 10 m high and 500 m apart, the walls pierced with loopholes for musketry in two stages (Fig. 1.8). They were designed for musket fire because of the shortage of cannon at that time. Later, at the onset of the Napoleonic Wars, each tower roof was reinforced and received a 12-pounder carronade (a short, smoothbore, cast-iron can- non), on a pivot mount that allowed 360 deg of rotation. Twenty-two round towers and one square tower were eventually built by 1798; a further three round (Martello)4 towers between 1807 and 1814; and five more between 1834 and 1838 (e.g. Fig. 1.9)—31 towers in total. Jersey contains both the earliest and the latest exam-

4 Inspired by a tower at Mortella Point on the Mediterranean island of Corsica that resisted consid- erable British naval bombardment in 1794, coastal towers of this type were built in England and across the British Empire during the nineteenth century. Round towers with thick masonry walls, Martello towers were resistant to cannon fire and their height (about 12 m) made them an ideal platform for a single heavy gun. 12 E. P. F. Rose and J. T. Renouf

Fig. 1.8 Le Hocq tower (number 18 on Fig. 1.4), a typical example of the Jersey round towers completed between 1780 and 1798 during the threat of invasion from revolutionary France, built initially to defend potential landing areas (at a time when there was a shortage of artillery) by musket fire from loopholes and the roof. Floor openings in the parts which jut out at the top of the tower enabled the defenders to fire straight down the walls whilst protected from enemy fire, and so prevent the enemy from undermining the tower. Photo by Paweł “pbm” Szubert, from Wikimedia Commons, file Jersey_Le_Hocq_Tower_01.jpg, reproduced under the terms of the Creative Commons Attribution-Share Alike 3.0 Unported License ples of such British-built fortifications in Europe—which by 1838 fringed all but the steep and so amphibiously inaccessible northern coast of the island (Fig. 1.4). All but four of these granite-built towers were still standing at the time of the German occupation. Three were destroyed by the Germans to make way for other works, but many were modified for contemporary use (see Partridge 1976, p. 134). 1 Introduction 13

Fig. 1.9 Kempt tower (number 4 on Fig. 1.4), one of the five ‘Martello’ towers constructed on Jersey between 1834 and 1838. Elliptical rather than round in plan, with its thickest wall towards the sea, this contained a trefoil gun platform—and was designed for defence by artillery rather than by musketry. The door inserted at ground level was part of later adaptation for German use. The original design was for mid-level access by means of wooden steps, as also shown. These could be burnt if the tower was attacked, to deny an easy means of access to the attacker. Photo: E.P.F. Rose

The last British fortress to be constructed on Jersey, Fort Regent, was founded in 1806, when defensive works throughout the island were in hand to counter the threat from Napoleonic France, and completed in 1814 just as the threat came to an end (Davies 1971). By this time Elizabeth Castle was considered to be too isolated to be of much value, except as a refuge of last resort, and the extensive new fort was constructed on the granite-like rocky promontory overlooking St. Helier (Fig. 1.4). It was garrisoned by the British regular army until 1932, but from that date onward no longer regularly occupied. Ironically, the only shots ever fired in anger from the fort were by German occupying troops against Allied aircraft during World War II.

1.5 British Fortification of Guernsey

On Guernsey, the first stone-built fortification was also founded in the thirteenth century: Castle Cornet, sited on a rocky granitic (granodiorite) facing the island’s capital town, St. Peter Port (Fig. 1.10), from which it was accessible on foot at low tide. Built initially between 1206 and 1256, Castle Cornet (Fig. 1.11) was developed through later centuries as the island’s principal fortress (Barton 2003; Guernsey 14 E. P. F. Rose and J. T. Renouf

Fig. 1.10 Map of Guernsey indicating sites of existing British-built thirteenth to nineteenth cen- tury fortifications. After Robins et al. 2012( )

Museum Team 2008; Rose et al. 2012). The first structure comprised a keep, chapel, two courtyards and curtain walls. However, the island was captured by French troops in 1338 and the castle’s defences were improved prior to recapture by the English in 1345. Further and more major re-modelling took place between 1545 and 1548, and later that century, to counter improvements generally in artillery, but the keep and part of the living quarters were catastrophically destroyed in 1672 when a strike by lightning detonated the castle’s gunpowder magazine. Upgraded during the French Revolutionary and Napoleonic Wars of 1793–1815 with additional bar- racks, the castle later became a prison. During World War II it was occupied by a small garrison of German troops, and known as strongpoint ‘Hafenschloss’ (‘har- bour fortress’). German modifications were made in concrete rather than stone as formerly, to adapt it to contemporary warfare. 1 Introduction 15

Fig. 1.11 Castle Cornet, built on a granodiorite island facing St. Peter Port, Guernsey’s principal town (cf. Fig. 1.10). From Wikimedia Commons, file Castle_Cornet_2009_b.jpg, released into the public domain

Fig. 1.12 Aerial view the Château des Marais, also known as Ivy Castle (cf. Fig. 1.10). From Green (2002), courtesy of Mark Lewis of the Guernsey Press and Star, per Richard Digard

The Château des Marais (Figs. 1.10 and 1.12) or the ‘castle of the marshes’, also known as Ivy Castle, was another stone-walled foundation of the early thirteenth century (Barton 1981). Constructed in the north of Guernsey, it provided a refuge for the local population potentially safe from attack in the marshland. It was built in classic ‘motte-and-bailey’ form, typical of the period, with the top of an enclosed mound flattened, and a surrounding dug out with the soil used to level and raise a system of inner and outer defences. These structures were encircled by walls on new, solid ground, as the adjacent marsh had been drained by a channel cut towards the sea coast to the east. It was Guernsey’s principal fortified site for 20–30 years before the focal point shifted to Castle Cornet as the island’s main defensive 16 E. P. F. Rose and J. T. Renouf

Fig. 1.13 Entrance to Vale Castle, near Guernsey’s NE coast (cf. Fig. 1.10). Photo: E.P.F. Rose structure about 1250. Late in the eighteenth century, at the time of wars with France, the castle was re-fortified and the magazine and much of the existing stonework belong to this period. It later fell into decay, becoming an ivy-covered ruin. However, during World War II, it was occupied by German troops who built a bunker within its inner walls, and machine-gun posts and communication trenches which destroyed much of the archaeological evidence of the earlier motte-and-bailey structure. Vale Castle (Figs. 1.10 and 1.13) overlooks and protects the port of St. Sampson towards the NE end of the island (Barton 1989) and has spectacular views of the nearby islands of Herm and Jethou. A stone castle was founded on the site of an Iron Age earthwork, curtain walls, a gatehouse and buttresses being constructed from granite in the fifteenth and sixteenth centuries, and barracks added in the eighteenth century (although the barracks were later demolished). During World War II, German forces fortified both the castle and its surrounding area, erecting a large gun position on top of an earlier battery and several machine-gun posts in and around the castle. On Guernsey, artillery batteries on stone-built foundations existed on several headlands (particularly on the east coast) during the seventeenth century, and 15 round towers of distinctive local style were built in 1778 or shortly thereafter (Fig. 1.14). Three Martello towers (each mounting at least one 24-pounder carron- ade, to counter naval attack) were built in 1804. These three towers formed the nucleus of more extensive fortifications and artillery batteries, developing into three of the island’s nine forts (Fig. 1.15). Fort George, completed in 1812 near Guernsey’s main town St. Peter Port (Fig. 1.10), was built to become the main British military headquarters for the island. Three of the round towers were later destroyed, as were four of the round towers on Jersey, but all these British fortifications were thick-­ 1 Introduction 17

Fig. 1.14 One of Guernsey’s surviving 12 round towers, constructed in 1778–79 from local stone to deter possible French attacks. The towers are numbered sequentially, counter-­clockwise from St. Peter Port on the east coast. That shown is number 4, near Fort Le Marchant in the NE of the island (cf. Fig. 1.10). Built to one design, they allowed musket fire to cover all approaches to the tower. Similar to the earlier towers constructed on Jersey (see Fig. 1.8), they differed in several details, notably in possessing a slope at the base but in lacking projections for downward fire at the top. Photo: E.P.F. Rose

Fig. 1.15 Fort Hommet, on a headland overlooking Vazon Bay on Guernsey’s western coast (cf. Fig. 1.10). Built on the site of fortifications that date back to 1680, this consists of a central stone-­ built (cf. Fig. 1.9), constructed in 1804, together with the mid nineteenth century barracks and batteries that later extended it into a fort. Concrete fortifications were added during the German occupation of the island, including a casemate for a 105 mm calibre gun, to transform the headland into Strongpoint ‘Rotenstein’. Photo: E.P.F. Rose