Details

The monument includes the buried and earthwork remains of Offa's Dyke
immediately north east of Sedbury sewage works. Offa's Dyke generally consists
of a bank up to 3.5m high with an intermittent ditch to the west and quarries
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 256m long section of the Dyke is visible as a terrace standing to a
height of 2m, falling over a distance of about 8m. In 1996, the Manchester
University Centre for Anglo-Saxon studies excavated a section through the
terrace, revealing what they have interpreted as the remains of Offa's Dyke.
All fence and gate posts 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.

Source: Historic England

Reasons for Scheduling

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 north east of Sedbury sewage works
survives well. The terrace will have preserved part of the original
ground surface, predating the construction of the monument, and 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 Dyke and the building materials used.

Source: Historic England

Sources

Books and journals
Hill, D, Gloucestershire, Sedbury, Sewage Works, (1996)
Hoyle, J, Vallender, J, Offa's Dyke in Gloucestershire: Management Survay, (1997)

Source: Historic England