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.
The section of Offa's Dyke immediately south of Coxbury Farm survives
well. The terrace will have preserved part of the original ground
surface, predating the construction of the monument and, along with the
quarries to the east, will contain environmental evidence in the form of
organic remains which will relate both to the Dyke and to the landscape
within which it was constructed. The terrace will also contain evidence
relating to the methods of construction of the monument and the building
materials used.
Details
The monument includes the buried and earthwork remains of Offa's Dyke,
immediately south of Coxbury Farm. 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.
This 146m long section of the Dyke is visible as a terrace, with a break
in slope to the east which marks the location of the Offan quarries. The
terrace is about 4m wide and stands to about 1m high on its western face,
while the quarries are approximately 0.4m deep and 5m wide.
All wooden fence and gate posts, sign posts, stiles and walls are excluded
from the scheduling, although the ground beneath these features is
included.
MAP EXTRACT
The site of the monument is shown on the attached map extract.
