Reasons for Designation
Cross dykes are substantial linear earthworks typically between 0.2km and 1km
long and comprising one or more ditches arranged beside and parallel to one or
more banks. They generally occur in upland situations, running across ridges
and spurs. They are recognised as earthworks or as cropmarks on aerial
photographs, or as combinations of both. The evidence of excavation and
analogy with associated monuments demonstrates that their construction spans
the millennium from the Middle Bronze Age, although they may have been re-used
later. Current information favours the view that they were used as territorial
boundary markers, probably demarcating land allotment within communities,
although they may also have been used as trackways, cattle droveways or
defensive earthworks. Cross dykes are one of the few monument types which
illustrate how land was divided up in the prehistoric period. They are of
considerable importance for any analysis of settlement and land use in the
Bronze Age. Very few have survived to the present day and hence all well-
preserved examples are considered to be of national importance.
Despite minor damge to the southern end, the cross dyke 230m ENE of Great
Kimble church survives in very good condition. The form and composition of the
bank will provide evidence for the method of construction, which may include
traces of timber palisades erected along the top. The earlier ground surface
buried beneath the bank is a particularly valuable resource, capable of
providing information about prehistoric soil conditions and land use which
will, together with the primary silts within the ditch, indicate the nature of
the landscape in which the monument was set. The bank material and ditch fills
may also contain artefacts from which the period of use can be determined and
the function of the monument assessed.
The proximity of a second cross dyke near the neck of the spur is considered
to be of great interest as the relationship between the two sites will provide
insights into the division of land and the nature of prehistoric settlement in
the Chiltern Hills.
Details
The monument includes the remains of a prehistoric univallate dyke situated
near the tip of a narrow wooded spur extending westwards from the Chiltern
escarpment between Happy Valley and The Coombes, at the foot of which lies the
village of Great Kimble.
The dyke is orientated north east to south west, and extends for c.70m between
the upper slopes of the steep scarps on either side of the spur. Fragments of
Iron Age pottery have been collected from the old chalk quarry at the end of
the spur, from which the area receives its name of Ragpit Hill. The excavation
of the quarry has truncated a small section at the southern end of the dyke
which, it is thought, would have originally continued towards the 150m contour
line at the brink of the steep natural slope into Happy Valley. The ditch
averages 1.5m in width and 0.8m in depth, and lies at the foot of a artificial
scarp, 3m-4m in width, which is cut into the hillside at an angle of
approximately 45 degrees. The ditch is flanked on the eastern, downhill side
by an earthen bank measuring c.5m across and 1.3m high. The dyke is breached
by a single causeway near the centre of the spur. This is approximately 4m in
width and is thought to be comparatively recent in date. It is also crossed,
further to the north, by a small medieval or post-medieval boundary bank.
A second, similar cross dyke (the subject of a separate scheduling), runs
parallel to this feature, transecting the neck of the spur some 250m to the
east.
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.
