Ancient Monuments

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Aberlleiniog Fish Weir II

A Scheduled Monument in Llangoed, Isle of Anglesey (Ynys Môn)

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Latitude: 53.291 / 53°17'27"N

Longitude: -4.0628 / 4°3'46"W

OS Eastings: 262599

OS Northings: 379103

OS Grid: SH625791

Mapcode National: GBR 0Z2C.6Z

Mapcode Global: WH53W.KJKW

Entry Name: Aberlleiniog Fish Weir II

Scheduled Date: 31 October 2002

Source: Cadw

Source ID: 3899

Cadw Legacy ID: AN143

Schedule Class: Maritime

Category: Fish weir

Period: Post Medieval/Modern

County: Isle of Anglesey (Ynys Môn)

Community: Llangoed

Traditional County: Anglesey


The monument consists of the well-preserved remains of a fish weir, dating to the post-medieval period. A fish weir is usually characterised by a foundation of stone topped with a fence or row of stakes, often with nets attached forming an enclosure within a river or harbour and used for catching, or holding, fish. Aberlleiniog Fish Weir II is rectilinear, defined by spread banks of stone. The structure is unusual in that it does not appear to run from the shore, utilizing instead a raised natural stony bank some 150m from the shore as its inner end. The inner arm comprises a spread stone bank some 115m long and 12m wide. The outer arm runs at a right angle to the south-west and is 130m long, narrowing to 6.0m in width towards its far end. The apex of the main weir is elongated, probably marking the remains of a sluice. A spur runs out from the centre of the outer arm into the channel. The function of this feature is unclear but it could be seen as a later addition or as the remains of an earlier phase.

The monument is of national importance for its potential to enhance our knowledge of medieval or post-medieval maritime agricultural practices. Being associated with Aberlleiniog I (SH 6250 7920) and standing within 1km of the weirs at Gorad Friars Bach (SH 6150 7770) and Trecastell (SH 6210 7860), the site has significant group value. It retains significant archaeological potential, with a strong probability of the presence of associated archaeological features and deposits. The structure itself may be expected to contain archaeological information concerning chronology and building techniques. The presence of anaerobic silts indicates that the site could retain preserved wood.

The scheduled area comprises the remains described and areas around them within which related evidence may be expected to survive.

Source: Cadw

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