Gwynedd Archaeological Trust
Regional Historic Environment Record

Weir Beneath Gorad Ddu, Llanfair Pwllgwyngyll

Primary Reference Number (PRN) : 14617
Trust : Gwynedd
Community : Llanfair Pwllgwyngyll
Unitary authority : Ynys Mon
NGR : SH54647159
Site Type (preferred type first) : Medieval FISH WEIR
Status : Scheduled Monument

Description :
A 4m wide linear bank of small stones runs through the centre of the area enclosed by Gorad Ddu. This appears to be the remains of an earlier trap. Further ill-defined walls can be seen on the outside of Gorad Ddu which may be associated with this site. (Hopewell, 2000).

There are the remains of a wall running north south, at right angles to the shore within Gorad Ddu. This badly collapsed structure, which, in places, is represented by a spread of small stones, can be traced for 65m and terminates in the accumulation of fine silt just north of the main weir wall. It may represent the remains of an earlier fish weir constructed in the same design as Gorad y Gyt on the southern side of the Menai Straits (GAT I 997).

On the seaward side of the main wall of Gorad Ddu, close to the rocky outcrop, is another construction of large boulders as shown in Fig 2. Even at very low tides this is difficult to identify but it appears to consist of a wide wall extending 80m in a south-easterly direction from the base of the main weir. It then turns at an acute angle to the south-west and continues for a further 20m. This section shows more clearly along the inner face of the wall. The masonry at this apex appears to be I Om wide but at no time during the survey was it entirely clear of the sea to allow a close or full inspection. This structure may represent part of an earlier fish trap although it does not align with the remains of the earlier wall to the north. It is unlikely that this is the hook-end of a fish trap as it is facing the wrong way to catch fish on an ebb tide. Some fish traps were designed to operate on the flood tide but they need a nonreturn opening at the apex that is not apparent in this case (Davis 1958, 30). If this structure is part of an earlier fish weir it would indicate a considerable rise in sea level in the area as it would not be possible to harvest the catch on any but the very lowest tides today. Momber suggested such a rise during a study of Gorad Beuno near Caernarfon a few miles west of Gorad Ddu. He found a net sea level rise in Caernarfon Bay of about 3m in the last millennium (Momber 1991, 108). (Richards, 1998),

Sources :
Hopewell, D. , 2000 , An Assessment of Coastal Fish Weirs and Traps. ( © )
Richards, A. , 1998 , Coastal Erosion Project: Fish Weir Survey ( © GAT)
Hopewell, D. , 2000 , An Assessment of Coastal Fish Weirs and Traps , <1>

Events :
40492 : An Assessment of Coastal Fish Weirs & Traps (year : 2000)

Related PRNs :

Compiled date : 26-05-2000

The above data are supplied by GAT in partnership with its Local Authorities (Anglesey, Conwy and Gwynedd County Councils, and Snowdonia National Park Authority), © GAT 2019 (and in part © Crown, 2019 - as indicated)
This information is supplied for the purposes of personal interest only and may not be used as part of a commercial project.

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