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Geologists in Wales: a distinguished history

The science of geology owes much to the exceptional importance and diversity of rocks in Wales. Over the last 200 years, many distinguished geologists have worked here and made discoveries for geological science out of all proportion to the size of our country.

A distinguished history

Wales has had a major influence on the science of geology and this is reflected in the global use of the terms Cambrian, Ordovician and Silurian to describe rocks of Lower Palaeozoic age. Welsh place names such as Arenig, Llandovery and Tremadoc are also used to subdivide these larger periods.

The use of names associated with Wales is linked to the development of geology in the 19th century, but there are references to Welsh geology that date from much earlier. For example, Gerallt Gymro (Giraldus Cambrensis) referred to pyritous shales from areas near Newport in the 12th century and Leland recognised the differences between coals from different areas in the 16th century.

At the end of the 17th century, Edward Llwyd published a catalogue of fossils and minerals in the Ashmolean Museum, Oxford, which contained many specimens collected in Wales. Early mapping of the British Isles also included studies of Wales and William Smith, the ‘father of British geology’, outlined the general structure of the South Wales Coalfield as part of his famous map of 1815. In 1822, Henslow published the first geological map of Anglesey.

The Victorian era

This period and the years immediately preceding saw the first intensive phase of geological study in Wales. In 1831 Adam Sedgwick, accompanied initially by Charles Darwin, commenced fieldwork in North Wales and began to unravel the complex geology of Snowdonia. In 1835 the term Cambrian was used in a joint paper by Sedgwick and Roderick Murchison, who had been working on younger rocks in the Welsh Borderlands. This initial co-operation developed into a bitter debate after it became clear that the lower part of the Silurian, coined by Murchison, actually overlapped with part of Sedgwick’s Cambrian. This was only resolved following their deaths when Charles Lapworth introduced the Ordovician System in 1879. Much of this controversy was played out with the rocks of Wales at the centre of the debate.

Maps, and corresponding memoirs, play a central role in geology. Following the creation of the Geological Survey in 1835 a great deal of work was carried out in Wales, often driven by the Industrial Revolution and the increasing demand for raw materials. One of the leading lights in this early mapping work was A. C. Ramsay, who was involved in the publication of Geology of South Wales and Geology of North Wales. By 1879 a geological map of Wales at a scale of one inch to four miles had been published.

The 20th century

One of the greatest individual mapping feats was carried out by Edward Greenly, who resigned from the Geological Survey to embark on a self-imposed geological survey of Anglesey. Greenly’s map (1920) and memoir (1919) have not been superseded. The 1920s saw much work in the north and eastern parts of Wales, with publication of the Wrexham, Flint, Liverpool and Oswestry maps. During the Second World War the Geological Survey concentrated on mineral resources, and much of this work formed the basis of later revisions to the geological maps of Wales.

The latest phase of systematic work by the Geological Survey (re-named the Institute of Geological Sciences and later the British Geological Survey) began in the 1960s with the mapping of Silurian rocks in Denbighshire. This programme was extended westwards into Conwy and eventually Snowdonia and culminated in a number of maps at a more detailed scale of 1:25,000, with accompanying booklets called the Classic Areas of British Geology. More recently the British Geological Survey has been mapping the Lower Palaeozoic rocks of mid-Wales from Aberystwyth across to Rhayader and Builth Wells as well as farther south, for example in the Lampeter and Llandovery districts.

On this site, we profile a selection of geologists who have made key contributions to the understanding of the geology of Wales. Many learned their profession here. If you think others merit inclusion please let us know…

Individual geologists have contributed a huge amount to our understanding of the geology of Wales.

Alongside the mapping work of the Geological Survey and its successor bodies, much of the foundation work on stratigraphy and palaeontology was undertaken by individual academics. This was of great help to the surveyors. Work on graptolites by Gertrude Elles, Ethel Wood and Margaret Crossfield laid the foundation for the accurate biozonation for much of the Silurian and Ordovician rocks of Wales.

Similarly, research work carried out by geologists such as A. Trueman, T. N. George, P. G. H. Boswell and O.T. Jones clarified the stratigraphy of various parts of Wales. Other key geologists who were instrumental in unravelling the complex geology of Wales include Howel Williams with his early work on the volcanic rocks of Snowdonia and Robert Shackleton with his pioneering work on the complex and deformed rocks of North Wales. Shackleton left a further legacy of ‘geological descendants’, including Dennis Wood, Nick Rast and Mike Coward, all of whom made important contributions to Welsh geology.


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