Details

The monument includes a hilltop enclosure and an earthern mound interpreted as
a pillow mound situated on the spur of Knowle Hill, a prominent chalk ridge of
the Isle of Purbeck, overlooking Poole Harbour to the north east. The hilltop
enclosure lies at the centre of a group of cross dykes on Knowle Hill.
The hilltop enclosure covers an area of 3ha, and is defined by steep natural
slopes to the north and south and cross dykes to the east and west. The
western cross dyke includes two parallel banks, aligned north-south and
divided by a quarry ditch. The banks have maximum dimensions of 49m in length,
8m-8.5m in width and c.0.45m-0.9m in height. The quarry ditch is 6.7m wide and
c.0.97m deep. A gap in both banks and corresponding causeway across the ditch,
30m from the southern end, is likely to mark an original entrance. This cross
dyke is likely to represent the most substantial set of earthworks built on
the hilltop during the Iron Age period.
The cross dyke to the east includes a bank and outer quarry ditch. It is
aligned broadly north-south, although the southern section deviates towards
the south west and creates a bowed appearance in plan. The bank has maximum
dimensions of 90m in length, 5m in width and c.0.4m-0.5m in height. The quarry
ditch has become largely infilled, but is known from survey to have maximum
dimensions of 6.5m in width and c.1m in depth. To the north, the cross dyke
joins with another earthwork. This takes the form of a bank with quarry ditch
to the north, aligned east-west, extending for 60m. The bank is 1.5m wide and
the ditch 3m wide. At the eastern end, the quarry ditch extends almost to the
edge of the natural scarp, where it forms a right angle with the eastern cross
dyke. However, at the western end, the earthwork deviates for approximately 2m
to the south of the adjacent northern scarp edge.
The interior of the hilltop enclosure covers an area of c.3ha and is known to
contain a large group of irregular hollows on the northern side. Part
excavation of the largest of these revealed the remains of four post holes and
clay floor levels, indicating the former presence of a timber built structure,
2.4m square in plan. Similar structures are known from other Iron Age
settlement sites, such as at Little Woodbury, Wiltshire. Occupation debris
including Iron Age pottery, animal bones, teeth, horns and antler and
Kimmeridge shale bracelets were recovered. The abundance of cattle remains
indicates a dependence upon a pastoral economy, although the working of
Kimmeridge shale was also significant.
The pillow mound, which is situated on the crest of the hill, has a mound
composed of earth, flint and chalk with maximum dimensions of 18m in length,
9m in width and c.0.55m in height. It was constructed during the medieval
period and might be associated with a group of similar monuments situated 600m
to the south west, in the valley bottom.
Excluded from the scheduling are all fence posts relating to the field
boundaries and the bench, although the underlying ground is included.

MAP EXTRACT
The site of the monument is shown on the attached map extract.
It includes a 2 metre boundary around the archaeological features,
considered to be essential for the monument's support and preservation.

Source: Historic England

Reasons for Scheduling

Hilltop enclosures are defined as sub-rectangular or elongated areas of
ground, usually between 10ha and 40ha in size, situated on hilltops or
plateaux and surrounded by slight univallate earthworks. They date to between
the Bronze Age and Early Iron Age (eighth-fifth centuries BC) and are usually
interpreted as stock enclosures or sites where agricultural produce was
stored. Many examples of hilltop enclosures may have developed into more
strongly defended sites later in the Iron Age period and are therefore often
difficult to recognise in their original form. The earthworks generally
consist of a bank separated from an external ditch by a level berm. Access to
the interior was generally provided by two or three entrances which consisted
of simple gaps in the rampart. Evidence for internal features is largely
dependent on excavation, and to date this has included large areas of sparsely
scattered features including post and stakeholes, hearths and pits.
Rectangular or square buildings are also evident; these are generally defined
by between four and six postholes and are thought to have supported raised
granaries. Hilltop enclosures are rare, with between 25 and 30 examples
recorded nationally. A greater number may exist but these could have been
developed into hillforts later in the Iron Age and could only be confirmed by
detailed survey or excavation. The majority of known examples are located in
two regions, on the chalk downland of Wessex and Sussex and in the Cotswolds.
More scattered examples are found in north-east Oxfordshire and north
Northamptonshire. This class of monument has not been recorded outside
England. In view of the rarity of hilltop enclosures and their importance in
understanding the transition between Bronze Age and Iron Age communities, all
examples with surviving archaeological remains are believed to be of
national importance.

The hilltop enclosure and pillow mound on Knowle Hill survive comparatively
well and are known from part excavation to contain archaeological and
environmental evidence relating to the monument and the landscape in which it
was constructed. The hilltop enclosure represents a rare example of its class
within Dorset and its value is enhanced by the preservation of associated
cross dyke systems on the hilltop, as these relate to the wider use of the
hilltop during the Iron Age. This, together with the preservation of other
Iron Age settlements nearby, will provide an important opportunity to contrast
the differing forms of settlement, land use and economic practices of the
period. The pillow mound, used in the medieval period for rabbit breeding, is
one of few examples to occur within monuments of an earlier date in Dorset and
is associated with a group of similar monuments nearby. Together these will
provide an insight into the use of warrens in this area of the country.

Source: Historic England

Sources

Books and journals
Historical Monuments in the County of Dorset: Volume I, (1970), 509
Historical Monuments in the County of Dorset: Volume I, (1970), 509
Historical Monuments in the County of Dorset: Volume I, (1970), 518
Historical Monuments in the County of Dorset: Volume I, (1970), 518
Historical Monuments in the County of Dorset: Volume I, (1970), 518
Historical Monuments in the County of Dorset: Volume I, (1970), 518
Historical Monuments in the County of Dorset: Volume I, (1970), 509
Historical Monuments in the County of Dorset: Volume I, (1970), 509
Historical Monuments in the County of Dorset: Volume I, (1970), 509
Historical Monuments in the County of Dorset: Volume I, (1970), 509
Historical Monuments in the County of Dorset: Volume I, (1970), 518
Historical Monuments in the County of Dorset: Volume I, (1970), 509
Historical Monuments in the County of Dorset: Volume I, (1970), 509
Historical Monuments in the County of Dorset: Volume I, (1970), 509
Historical Monuments in the County of Dorset: Volume I, (1970), 509
Historical Monuments in the County of Dorset: Volume I, (1970), 509
Historical Monuments in the County of Dorset: Volume I, (1970), 509
Historical Monuments in the County of Dorset: Volume I, (1970), 509
Historical Monuments in the County of Dorset: Volume I, (1970), 518
Historical Monuments in the County of Dorset: Volume I, (1970), 481
Grinsell, L V, 'Procs Dorset Natural History and Archaeological Soc.' in Dorset Barrows, (1959), 78

Source: Historic England