Site of Iron Age fort, Porth y Rhaw

Site of Iron Age fort, Porth y Rhaw, near Solva

The headland east of Porth y Rhaw was once home to a large promontory fort, much of which has been lost because of coastal erosion. Porth y Rhaw is also an important geological site, rich in fossils. The cliffs are unstable – please keep to the path.

Photo of trilobite fossil found at Porth y Rhaw
Paradoxides davidis fossil from Porth
y Rhaw © Amgueddfa Cymru
– National Museum Wales

The fort was designed to use the natural slope on the north side for defence against attack from the land. The cliffs provided protection on the other sides. There were three parallel rows of ditches and banks on the north side. Lower down was a fourth row, in a straighter line (possibly dug at a different time). The rows are clearly visible in the aerial map image below.

Erosion has reduced what remains of the fort's interior into two small opposing promontories.

Archaeologists have found on the site the remains of at least eight roundhouses, mostly made of timber. One had been rebuilt using stone. Objects found there indicated that people lived at the fort from c.600BC to c.350AD.

Mesolithic flint was also discovered – indicating that humans used the land here long before the fort was created.

In 1862 palaeontologist John Salter landed at Porth y Rhaw in his boat, thinking he had reached Solva. He had made a fortunate mistake, because he stumbled across a type of trilobite fossil which he later named Paradoxides davidis, after amateur fossil collector David Homfray of Porthmadog. Normally fossilised trilobites are about 2cm to 3cm long – but John found one measuring more than 50cm!

Porth y Rhaw is one of relatively few places in Wales where fossils from c.485-515 million years ago (during the Cambrian period) are easily found. The photo shows one of the trilobite fossils from Porth y Rhaw in the Amgueddfa Cymru – National Museum Wales collection.

With thanks to Fran Murphy, of Dyfed Archaeological Trust, and to Amgueddfa Cymru – National Museum Wales

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