Cantre'r Gwaelod - Physical Evidence

Physical Evidence

There is no reliable physical evidence of the substantial community that legend promises lies under the sea, although several reports exist of remains being sighted.

In 1770, Welsh antiquarian scholar William Owen Pughe reported seeing sunken human habitations about four miles (6.4 km) off the Ceredigion coast, between the rivers Ystwyth and Teifi.

In the 1846 edition of The Topographical Dictionary of Wales, Samuel Lewis described a feature of stone walls and causeways beneath the shallow waters of Cardigan Bay:

In the sea, about seven miles west of Aberystwyth in Cardiganshire, is a collection of loose stones, termed Caer Wyddno, "the fort or palace of Gwyddno;" and adjoining it are vestiges of one of more of the more southern causeways or embankments of Catrev Gwaelod. The depth of water over the whole extent of the bay of Cardigan is not great; and on the recess of the tide, stones bearing Latin inscriptions, and Roman coins of various emperors, have been found below high-water mark: in different places in the water, also, are observed prostrate trees."

— Samuel Lewis, The Topographical Dictionary of Wales.

Lewis takes the view that maps by the cartographer Ptolemy marked the coastline of Cardigan Bay in the same location as it appears in modern times, suggesting that the date of the flood occurred before the second century AD.

The "causeways" described by Lewis can be seen today at beaches around Cardigan Bay. Known as Sarnau, these ridges stretch several miles into the sea at right angles to the coast, and are located between each of the four river mouths in the north of Cardigan Bay. Modern geologists surmise that these formations of clay, gravel and rocks are moraines formed by the action of melting glaciers end of the last Ice Age. In a 2006 episode of the BBC television documentary Coast, presenter Neil Oliver visited Sarn Gynfelyn at Wallog. The programme also featured the remains of the submerged forest at Ynyslas, near Borth which is associated with the lost land of Cantre'r Gwaelod. The vista of dead oak, pine, birch, willow and hazel tree stumps preserved by the acid anaerobic conditions in the soil is revealed at low tide and is estimated to be about 5000 years old.

In 2006, a scientific underwater exploration was undertaken by the conservation group Friends of Cardigan Bay to examine the submerged forest and search for evidence of Cantre'r Gwaelod.