Reasons for Designation
Offa's Dyke is the longest linear earthwork in Britain, approximately 220km,
running from Treuddyn, near Mold, to Sedbury on the Severn estuary. It was
constructed towards the end of the eighth century AD by the Mercian king Offa,
and is believed to have formed a long-lived territorial, and possibly
defensive, boundary between the Saxon kingdom of Mercia and the Welsh
kingdoms.
The Dyke is not continuous and consists of a number of discrete lengths
separated by gaps of up to 23km. It is clear from the nature of certain
sections that differences in the scale and character of adjoining portions
were the result of separate gangs being employed on different lengths. Where
possible, natural topographic features such as slopes or rivers were utilised,
and the form of Offa's Dyke is therefore clearly related to the topography.
Along most of its length it consists of a bank with a ditch to the west.
Excavation has indicated that at least some lengths of the bank had a vertical
outer face of either laid stonework or turf revetment. The ditch generally
seems to have been used to provide most of the bank material, although there
is also evidence in some locations of shallow quarries. In places, a berm
divides the bank and ditch, and a counterscarp bank may be present on the lip
of the ditch.
Offa's Dyke now survives in various states of preservation in the form of
earthworks and, where sections have been levelled and infilled, as buried
features. Although some sections of the frontier system no longer survive
visibly, sufficient evidence does exist for its position to be accurately
identified throughout most of its length. In view of its contribution towards
the study of early medieval territorial patterns, all sections of Offa's Dyke
exhibiting significant archaeological remains are considered worthy of
protection.
Details
The monument includes the buried and earthwork remains of Offa's Dyke,
370m west of Birt's Barn, in Highbury Plains. Offa's Dyke generally
consists of a bank up to 3.5m high with an intermittent ditch to the west
and quarry ditches to the east. In places Offa's Dyke was strengthened by
additional earthworks, namely a berm between the bank and ditch and a
counterscarp bank on the western lip of the ditch.
In this section, the Dyke is visible as a bank with quarry pits. The bank
is about 10m wide at its base and stands to a maximum height of 2.5m on its
western face and 1m on its eastern face. To the east of the bank are a series
of quarry pits which are up to 8m wide and 0.4m deep. Deliberately laid
stonework has been exposed at intervals along the western face of the bank,
and may be interpreted as the remains of a dry stone revetment acting as a
near vertical, and highly visible, facing to the western side of the Dyke. The
lime kiln shown by the Ordnance Survey to the east of the line of the Dyke is
in a ruinous condition, and is thought to date to the 19th century.
The line of the Dyke is interrupted by a track which is now called Coxbury
Lane and is thought to be an ancient routeway leading to Wyegate, an early
medieval manor about 2km to the south of the point where the lane crosses
the Dyke at Highbury. Where the lane crosses the Dyke, it is included in
the scheduling.
All fences, fence posts, gates, stiles, sign posts and the remains of the
lime kiln are excluded from the scheduling, although the ground beneath
these features is included.
Legacy
The contents of this record have been generated from a legacy data system.
Legacy System number:
33453
Legacy System:
RSM
Sources
Books and journals
Legal
This monument is scheduled under the Ancient Monuments and Archaeological Areas Act 1979 as amended as it appears to the Secretary of State to be of national importance. This entry is a copy, the original is held by the Department for Culture, Media and Sport.
End of official list entry
