Archaeologists working on the 2,500-year-old Dinas Dinlle hill fort on the Gwynedd coastline in Wales are racing a climate change clock to uncover the site’s secrets before they are lost to the sea. The bad news is there’s an ever-present threat of the eroding western edge of the site, the good news is there are probably hundreds of years before the whole site will drift away, so they should be able to unearth much of Dinas Dinlle’s archaeological treasures before then.

History of the Dinas Dinlle Iron Age Fort

Dinas Dinlle fort is located on a hill of glacial drift on the Caernarfonshire coastal plain. The unstable nature of the soil is a major cause of concern and explains much of the loss of land and the western side of the defensive walls. It is owned by the National Trust.

The earliest recognized structures of the fort have been dated to the Iron Age . Today these are visible as a double semi-circular rampart and a recently uncovered 43-foot-wide (13-meter-wide) roundhouse. Discussing the roundhouse, David Hopewell, senior archaeologist at the dig, said “It's probably the biggest one I've ever seen in 30 years of archaeology.”

The roundhouse was buried under three feet (one meter) of sand which experts believe may have blown over it during a storm in 1330. Hopewell believes that a trench found nearby may indicate the presence of another roundhouse.

The Independent reports that archaeological teams have also unearthed come Roman coins, an intaglio (gemstone for a ring), and pottery over the years, which may suggest either a Roman inhabitation of the site around the 2nd or 3rd century AD or an interaction with the Romans and another tribe that may have lived there. The archaeological team also think that “the prominent, squarish stone mound inside the fort” may indicate a Roman pharos (lighthouse) and that “early medieval occupation of this prominent site is also very likely.”

And the site was revisited and reused over time, according to Coflein, “the lower north-facing ramparts of the fort” had a WWII Seagull Trench built into them. And the Royal Commission on the Ancient and Historical Monuments of Wales states that it was used as a pill box and observation post at that time. The site also formed part of a golf course in the early 20th century.

The Dinas Dinlle coastal fort is an Iron Age hill fort experts have identified as under the threat of climate change. Source: Crown Copyright

Climate Change Takes its Toll But the End is Not Nigh…Yet

BBC News reports that the Dinas Dinlle fort has been chosen as “one of the 12 sites in the UK and Ireland being monitored by the European Union-funded Cherish project ” to monitor the impact of climate change on coastal sites. Experts have noted consistent erosion on the western, and more recently southern end, of the fort.

However, experts believe there is still time before the whole site will disappear. In fact, estimates suggest that there are some 500 years left before the Dinas Dinlle site may be destroyed in its entirety.

Nonetheless, the encroaching coastline is a real threat to discovering at least some of the secrets which lay within the soil. Experts believe that 30% of the site has “already been lost to the Irish Sea since 1900,” according to the BBC.

There is time, but will it be enough? What archaeological treasures will be lost to the sea before archaeologists can return to the site…if they do?

According to The Independent, the most recent dig was examining “numerous possible roundhouses and other anomalies within the interior of the fort”.

Andy Godber of the National Trust suggests that there is still some hope; even if the site can’t be saved, some of its history can be salvaged. He said:

“Dinas Dinlle encapsulates the risk to our coastline from climate change. Our coastal adaptation policy for Dinas Dinlle is to accept the loss of this important site, being part of this innovative project allows us to learn more about the history of human occupation here, while we still can."

WalesOnline reports that there are still a couple more years for the CHERISH team to work on Dinas Dinlle. Louise Barker, a senior archaeologist on that project said, “This is one of the finest coastal heritage sites in north Wales, but is threatened by active erosion. Through our work we hope to gain a better understanding of when Dinas Dinlle was built and occupied, and how much has been lost to the sea.”

A 3D computer model of the eroding fort generated from aerial photography will allow archaeologists to measure the rate of coastal erosion. ( Royal Commission on the Ancient and Historical Monuments of Wales )

The most recent excavations come to an end today. Now it’s time to analyze the findings and plan for the next round!

Top Image: An aerial photograph of Dinas Dinlle Iron Age Hill Fort from the north (suffering from coastal erosion); Gwynedd, Cymru / Wales. Cromlechs & Ancient Sites. (CADW/Visit Wales/ CC BY SA 3.0 )

By Alicia McDermott