The Bailiwick of Guernsey consists of the Islands of Guernsey (Sarnia), Herm, Sark and Alderney, plus sundry smaller islands such as Lihou, Jethou and Burhou. The island of Guernsey covers an area of nearly 25 square miles (or 40 square kilometers).
The Channel Islands came under the British crown when William, Duke of Normandy invaded England in 1066. Since that time, the Guernsey has remained in English hands, despite the loss of mainland France. There was a brief break in the English rule between 1338 and 1345. The last significant threat from France came during the Napoleonic wars, during which the Island’s defenses were strengthened by the ubiquitous Martello towers. The Second World War saw the German Occupation, since the Channel Islands were considered to be indefensible against modern warfare techniques. The Queen’s official title in the Bailiwick of Guernsey, to this day, is that of the Duke of Normandy.
To the islanders, St Peter Port is commonly referred to as "town".
We were very fortunate in being able to have very patient Dave Dorey, David De Lisle and Andy Dorey from La Société Guernesiaise as our guides over the Easter Weekend. Their local knowledge proved invaluable when all the awkward questions started to appear.
There is a very good general geological publication available for those interested in Guernsey's geology which costs about £4 (Easter 2001) called "The rocks and scenery of Guernsey" ISBN 0-9518075-2-8. This book was used throughout the weekend and I would recommend it to anyone visiting the island that has any interest in the geology of this lovely place.
References and Further Reading
BGS Map Channel Islands Sheet I Solid and Drift 1:25000
"The Rocks and Scenery of Guernsey" Mick de Pomerai & Andy Robinson 1994 published by La Société Guernesiaise.
"Outline and Guide to the Geology of Guernsey (with map)" RA Roach c 966, reprinted from La Société Guernesiaise Report and Transactions, Volume XVII. (pale green A5 paperback booklet)
"Outline and Guide to the Geology of Guernsey" RA Roach, CG Topley, M Brown, AM Bland and RS D’Lemos, Guernsey Museum Monograph No 3, 1991.
"Geochronology of the Channel Islands and adjacent French mainland" CJD Adams, Journal of the Geological Society, Volume 132 Part 3, May 1976.
Acknowledgement
Thanks are due to La Société Guernesiaise for their permission to reproduce the colour geological map of Guernsey from "The Rocks and Scenery of Guernsey"