image: The Black Book of Carmarthen (1250 approx) is believed to be the earliest surviving complete manuscript written in the Welsh language. This extract says, in Welsh: ‘Stand forth, Seithenhin, and look upon the fury of the sea; it has covered Maes Gwyddneu.’ The new research on the evolution of the coastline in west Wales suggests that claims such as this of a drowned land are plausible. view more
Credit: Llyfrgell Genedlaethol Cymru/National Library of Wales.
A Welsh tradition dating to the medieval period of a landscape lost to the sea is plausible, new evidence on the evolution of the coastline of west Wales has revealed.
Drawing on geological data and a medieval map, the researchers – from Swansea University and the University of Oxford – propose how two islands may have come into existence and then disappeared again.
The study was inspired by the Gough Map, the earliest surviving map of Great Britain, perhaps with its origins in the thirteenth century, which is held in the University of Oxford’s Bodleian Library.
The map depicts two islands in Cardigan Bay in west Wales, which no longer exist. Each of them is depicted about one quarter of the size of the island of Anglesey in north Wales. One is between Aberystwyth and Aberdovey and the other between there and Barmouth to the north.
The research was undertaken by Simon Haslett, Honorary Professor of Physical Geography at Swansea University and David Willis, Jesus Professor of Celtic at the University of Oxford.
Their study investigates historical sources and geological evidence from the coastline and the seabed. It proposes a model for how the coast has evolved since the last ice age around 10,000 years ago, which provides a possible explanation for the ‘lost’ islands.
They suggest that the islands could be the remnants of a low-lying landscape underlain by soft glacial deposits laid down during the last ice age. Since then, forces of erosion have worn away the land, reducing it to islands, before these too were worn away and disappearing by the sixteenth century.
As finer sediments of glacial deposits are eroded away, the larger gravel and boulder component is left on the seafloor. The position of the islands coincides with the location of submarine accumulations of gravel and boulders, known locally as sarns.
Professor Simon Haslett of Swansea University Department of Geography said:
“We know that the west Wales coast has changed significantly over time. Evidence from the Roman cartographer Ptolemy suggests the coastline 2000 years ago may have been some 13 km further out to sea than it is today.
The Gough Map is extraordinarily accurate considering the surveying tools they would have had at their disposal at that time, and the two islands are clearly marked.
Our research increases our understanding of potential coastal processes acting along the coast of Cardigan Bay. It can also help with future research on post-glacial evolution of similar lowlands in other parts of northwest Europe.
Understanding coastline dynamics has never been more important. Some towns along the area we studied are vulnerable to climate and sea-level change, and it has been suggested that it may lead to some of the first climate change refugees in the UK”.
David Willis, Jesus Professor of Celtic Studies at the University of Oxford, said:
Our evidence may provide an explanation of how the story of Cantre’r Gwaelod (‘The Hundred of the Bottom’) may have arisen. This lost land is said to have suffered a catastrophic inundation and is referred to in poetry in the Black Book of Carmarthen and in later folklore.”
The research was published in the journal Atlantic Geosciences and is available open access until 5 September 2022.
ENDS
Pictures: the relevant extract from the Gough map can be viewed at the link below. However, permission for use by media organisations must be sought from imaging@bodleian.ox.ac.uk
Notes to editors:
Swansea University is a world-class, research-led, dual campus university offering a first-class student experience and has one of the best employability rates of graduates in the UK. The University has the highest possible rating for teaching – the Gold rating in the Teaching Excellence Framework (TEF) in 2018 and was commended for its high proportions of students achieving consistently outstanding outcomes.
Swansea climbed 14 places to 31st in the Guardian University Guide 2019, making us Wales’ top ranked university, with one of the best success rates of graduates gaining employment in the UK and the same overall satisfaction level as the Number 1 ranked university.
The 2014 Research Excellence Framework (REF) 2014 results saw Swansea make the ‘biggest leap among research-intensive institutions’ in the UK (Times Higher Education, December 2014) and achieved its ambition to be a top 30 research University, soaring up the league table to 26th in the UK.
The University is in the top 300 best universities in the world, ranked in the 251-300 group in The Times Higher Education World University rankings 2018. Swansea University now has 23 main partners, awarding joint degrees and post-graduate qualifications.
The University was established in 1920 and was the first campus university in the UK. It currently offers around 350 undergraduate courses and 350 postgraduate courses to circa 20,000 undergraduate and postgraduate students. The University has ambitious expansion plans as it moves towards its centenary in 2020 and aims to continue to extend its global reach and realise its domestic and international potential.
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Journal
Atlantic Geoscience