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 on St Briavels Common, 90m north of The
Cherries survives well. The terrace will have preserved part of the
original ground surface, predating the construction of the monument, and
along with the quarries, 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 phases of the construction of the monument, the use of
building stone from the southern quarries, the use of stone or turf for an
outer facing and the use of wooden posts to mark the course of the
monument during its construction.
Details
The monument includes the buried and earthwork remains of Offa's Dyke, 90m
north of The Cherries. 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 it 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 turns from its usual alignment to run some 324m
east-west. It is visible as a terrace with quarry pits to the south. The
terrace is a maximum height of 2m, falling over about 6m. The quarry pits
cover an area some 4m to 5m wide and up to 1m deep.
In 1999, an archaeological observation during construction was undertaken
at Morgan's Cottage at the western end of the section. A feature within
one of the foundation trenches observed was found to be consistent with
the morphology of the bank in this area.
The wooden posts, gate posts, stone walls, Morgan's Cottage and all
buildings associated with it 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.
