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 Sittingreen survives well. The
bank will have preserved part of the original ground surface, predating the
construction of the monument and, along with the ditch and the quarries,
will contain environmental evidence in the form of organic remains which will
relate both to the Dyke and the landscape in which it was constructed.
The bank will also contain evidence relating to the methods of construction of
the monument as well as the building materials used.
Details
The monument includes the buried and earthwork remains of Offa's Dyke
immediately to the south of Sittingreen, on St Briavels Common. 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 stregthened 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 runs for some 173m. It is visible as a bank with a
ditch to the west and quarry pits to the east. The bank stands to about 1.7m
on its western face and to between 0.5m and 0.7m on its eastern face. The
ditch is approximately 7m wide and up to 0.4m deep, while the quarries cover
an area up to 6m wide and 0.6m deep. In the northern part of this section the
bank has been reduced through cultivation and landscaping in the past, and the
ditch and quarries have become infilled and are no longer visible at ground
level, although they will survive as buried features.
All wooden fence posts, gate posts and stone walls, driveways and garden sheds
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.
