This is a revised and expanded edition from the 1972 publication due to subsequent research in the post plate tectonic era, providing an up to the minute account of the British Ordovician formation and their correlation nationally and internationally. The British sections are the type for the Ordovician System and classical in stratigraphical, tectonic and volcanic studies. The Charts bring together thirty years of research over the period in which plate tectonics has revolutionised our understanding of the Lower Palaeozoic of the British Isles. Also includes comprehensive literature of papers published since 1970 and the most comprehensive treatment of Ireland ever attempted. Readership: UK and international stratigraphers, palaeontologists and field geologists researching rock of Ordovician age. Particularly those interested in the Welsh mountains and the Lake District of the UK. Also available: The Geology Of England And Wales - ISBN 1862391998 The Geology of Central Europe - ISBN 1862392455 The Geological Society of LondonFounded in 1807, the Geological Society of London is the oldest geological society in the world, and one of the largest publishers in the Earth sciences.The Society publishes a wide range of high-quality peer-reviewed titles for academics and professionals working in the geosciences, and enjoys an enviable international reputation for the quality of its work.The many areas in which we publish in include:-Petroleum geology -Tectonics, structural geology and geodynamics -Stratigraphy, sedimentology and paleontology -Volcanology, magmatic studies and geochemistry -Remote sensing -History of geology -Regional geology guides