Porth-y-Rhaw Promontory Fort

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Awdurdod Unedol (Lleol)Sir Benfro
Hen SirSir Benfro
CymunedSolva
Math O SafleCAER BENTIR
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Disgrifiad

1.

NAR SM72SE4
A heavily indented clifftop knoll is cut-off by a complex of earthworks, producing a segmented enclosure; the earthworks defining the eastern part of the site comprise a sweep of three banks with intermediate ditches, having an entrance towards the east, opening onto a heavily eroded promontory area; a series of terraces, with low banks, about 140m long, cut off the whole site; the relationship between these two sets of earthworks is unclear.
Excavation in 1996-7 demonstrated substantive Iron Age - Romano-British occupation in the eastern part of the site.

Sources: Crane 1997 (AW 37), 61;
1998 (AW 38), 102-3, 124-5.
RCAHMW AP945019/41-2; 965016/66
J.Wiles 12.09.2003

2.

Porth-y-Rhaw, the gnarled remains of a much-eroded coastal promontory fort to the west of Solva. Sweeping arcs of the banks and ditches cut off a protruding promontory from the coast, while the two `horns' to the east and west represent the remains of the interior. In response to ongoing coastal erosion which removed as much as three-quarters of the original fort, excavations were carried out during 1997-8 by Cambria Archaeology, focussed on the house platforms on the left-hand `horn'. Circular footings of at least eight round houses were discovered, some having been rebuilt five times. The fort probably began life in the Early to Middle Iron Age, but occupation continued into the Roman period, attested by radiocarbon dating and finds of fine Roman tableware. Metal working was carried out on site, as was the manufacture of glass beads similar to those found on Foel Trigarn inland (RCAHMW, 96-cs-0182).
Extract from: Driver, T. 2007. Pembrokeshire, Historic Landscapes from the Air, RCAHMW, page 107, Figure 161.

3.

2006 description of the site: Porth y Rhaw is a multivallate coastal promontory fort much reduced by coastal erosion. The c. 30m high sea cliffs have suffered erosion, so much so that the interior of the fort is now reduced to two small promontories, the eastern one 70m N-S and 25m E-W and the western one 70m SW-NE and 30m NW-SE. These two reduced promontories were undoubtedly once much larger, and probably formed a single block of unknown dimensions. The remains of the interior are relatively level, but immediately to the north of the interior land falls away quite steeply into a shallow valley. The defences make use of this slope, with the inner bank occupying the crest of the valley side, lending a monumental aspect to the whole site. There are four lines of bank and ditch in total. The three inner curving inner ones are close-set and parallel, and c. 120m long. The inner bank rises 4m above the ditch, the second bank is less substantial and rises just 1m above the ditch and the third 1m-2m above the ditch. The outer, fourth, bank is straighter than the others and its course diverges from them at its west end, perhaps indicating a separate phase of construction. Because of the slope the outer bank is almost 20m lower that the inner bank. The entrance has suffered from erosion, but a gap through the inner bank towards its eastern end close to the cliff edge marks its position. Terminals of the second and third banks stop short of the cliff edge - any continuation of these banks, if there were any, has been lost to the sea. Excavations in 1995-98 revealed the remains of at least eight timber roundhouses, some of which had been rebuilt several times, including one in stone. Radiocarbon dates indicate that occupation started in the early-to-mid Iron Age, and pottery indicates it continued into the 4th century AD.

Although a large portion of this site must have been lost to the sea, remote sensing analysis and comparison of historical data with modern data shows that this lost was prior to the surveying of the Ordnance Survey 1:2500 1st edition map of 1891. Detailing slight loss since then is problematic, and indeed modern aerial photographic sources seem to show a marginal gain of land over that shown on Ordnance Survey maps! Continuing loss of vegetation and soil cover was recorded; this loss should be monitored.

The geophysical survey detected the stone built roundhouse, partly excavated in the 1990s, and several of the timber-built roundhouses. Geophysical signals from the timber roundhouses were particular weak, and it is uncertain whether these would have been correctly interpreted without the excavation evidence.

Reference:

Page, M., Barker, L., Driver, T. and Murphy, K. 2008. Remote sensing and the Iron Age coastal promontory forts of Pembrokeshire, Archaeology in Wales 48, 27-38.

Crane, P and Murphy K 2010 `The excavation of a coastal promontory fort at Porth y Rhaw, Solva, Pembrokeshire? Archaeologia Cambrensis 159, 53-98

T. Driver, RCAHMW

4. 

New Cadw-funded excavation undertaken by the Dyfed Archaeological Trust was undertaken on the gateway and interior area during 2019, 2020 and 2021.  A number of structures were uncovered and excavated and the footprint and threshold of one of the stone roundhouses remains visible.

5.

New survey was undertaken at the monument as part of the CHERISH-Climate Change and Coastal Heritage Project  2017-2023. This included a new earthwork/topographic survey and UAV photogrammetric survey from which  a 3D model was created, and which can be accessed with the links below:

English: https://skfb.ly/6RGIz 

Cymraeg: https://skfb.ly/6RGI7

In February 2022 CHERISH also installed two fixed survey markers (survey nails in two earth-fast boulders) at the site. The markers and their associated location coordinates (BNG) will enable accurate monitoring and change detection at the site going forward. Details are:

E2 Primary Station Marker - Easting: 178742.369; Northing: 224229.8426; Height: 24.8951

E6 Secondary Control Point - Easting: 178762.7489; Northing: 224199.5636; Height: 29.1050

See CHERISH Monitoring Network - PR_E2 and PR_E6 control markers Event Report: 03/02/2022 for full details including Witness Diagrams (CHERISH Survey Report No. CH/RCAHMW 45 and Data Archive RCCS32).

CHERISH also funded the installation near to the site of a Changing Coasts Post, in Partnership with the Pembroekshire Coast National Park Authority. From this post the public can take and submit a fixed-point photography to help monitor erosion at the monumnet going forward.  More information about the post can be found here: https://www.pembrokeshirecoast.wales/get-involved/changing-coasts/ 

Louise Barker, CHERISH - RCAHMW, December 2023

CHERISH (Climate, Heritage and Environments of Reefs, Islands and Headlands) was an EU-funded Wales-Ireland project (2017-2023) led by the Royal Commission on the Ancient and Historical Monuments of Wales, in partnership with the Discovery Programme: Centre for Archaeology and Innovation Ireland, Aberystwyth University: Department of Geography and Earth Sciences and Geological Survey, Ireland.  https://cherishproject.eu/en/ .Crown copyright: CHERISH PROJECT. Produced with EU funds through the Ireland Wales Co-operation Programme 2014-2020. All material made freely available through the Open Government Licence.