Details

The monument includes an extensive area of Neolithic flint mines centred on
Martin's Clump, lying immediately below the crest of a chalk ridge, with a
linear boundary earthwork and two adjacent bowl barrows set on the ridge top,
in an area of undulating chalk downland on Porton Down.

Individual flint mines are visible as shallow surface depressions, generally
4m-5m across although some are as large as 8m. They are up to 0.2m deep and
some have small adjacent mounds representing excavated spoil. The north
western edge of the mined area is apparently delineated by a linear earthwork
of later prehistoric date. A detailed survey of the mined area was carried out
in 1996 by the Royal Commission on the Historical Monuments of England. A
total of 337 pits, or possible quarry features were recorded, covering an area
of about 4.5ha. In places, particularly at the northern end and towards the
south west, the pits tend to cluster closely together which may suggest that
relatively shallow seams of flint were being exploited.

The mines were first recorded by JFS Stone who identified three flint working
floors amongst the quarry pits. In 1932, together with J G D Clark, Stone
investigated one of these, recovering large quantities of flint working
debris. In 1954-5 a mine pit was excavated by Col Watson and was found to be
3m deep and up to 3.6m in diameter. Among the finds from this excavation were
flint axes and roughouts and an antler pick. In 1984 excavation by the CDE
Conservation Group identified four small but previously unknown mine pits,
each just over 1m in diameter and up to 1.5m deep. Finds again included worked
flint, axe roughouts and a complete axe.

A single radiocarbon date of around 4000 BC was obtained from antler found in
the 1984 excavation. This provides some of the earliest evidence for flint
mining in the British Isles. There is also evidence, from pottery and flints,
for the use of the site into the Bronze Age. In the 17th to 19th centuries
flint from the bank of the adjacent linear earthwork was used as raw material
by gun flint knappers.

The linear boundary is 1400m long and visible on two principal alignments,
south west to north east at the southern end and NNW-SSE at the northern end.
Excavation of a trench across the earthwork in 1984 revealed a `V' shaped
ditch to the north of an adjacent bank with an overall width of 10m and a
height for the bank above the bottom of the ditch of about 2m. Finds of flint,
pottery and bone were recovered from the section. An ox bone recovered from
the primary silt of the ditch gave a radiocarbon date of between 400 and 250
BC.

The monument includes two bowl barrows which lie adjacent to the later linear
boundary. The northernmost barrow has a mound 16m in diameter and 0.6m high in
the centre of which are traces of disturbance. These may represent the remains
of an unrecorded antiquarian excavation. Surrounding the mound, and best
preserved on the north side, is a ditch 2.5m wide and a maximum of 0.4m deep
from which material to construct the mound was quarried. The southernmost
barrow is bounded on its western side by the linear earthwork and on its
eastern by the flint mines. The barrow survives as an earthen mound 14m in
diameter and 0.7m high. Although no longer visible at ground level, a ditch,
from which material was quarried during construction of the barrow, surrounds
the mound. This has since become infilled but survives as a buried feature
about 3m wide. Worked flint artefacts visible on the surface of the mound are
probably remains from reuse of the site by the gun flint industry
rather than contemporary remains.

All fence posts and hardened track surfaces are excluded from the scheduling
although the ground beneath them 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

Since 1916 the Porton Down Range has been used for military purposes. As on
the Salisbury Plain Training Area, this has meant that it has not been subject
to the intensive arable farming seen elsewhere on the Wessex chalk. Porton, as
a result, is one of very few surviving areas of uncultivated chalk downland in
England and contains a range of well preserved archaeological sites, many of
Neolithic or Bronze Age date. These include long barrows and round barrows,
flint mines and evidence for settlement, land division and agriculture.

Flint mines are found where, during Neolithic and Early Bronze Age times
(c.3500-1200 BC), nodules of flint were extracted from underground seams
within chalk deposits. There is no pattern or regular form to the arrangement
of mine sites as the shafts, pits or open-cast workings are closely related to
the underlying supplies of flint rather than an overall scheme of how the
mine should be organised. In general, however, the shafts, pits and spoil-
heaps are closely packed together and sometimes even abut one another. In
overrall size, flint mines range from single shafts and associated works
covering less than 1ha, to large mines of several hundred shafts spread over
an extensive area. Flint mines provided high quality flint for implement
manufacture in the millennia before the widespread availability of metal; the
discovery of ceremonial deposits, including carved objects, in some shafts
indicates the importance ascribed to them by early prehistoric communities.
The workings were excavated by hand with antler picks and a selection of
specialist bone, antler, wood and flint tools. Extensive flint knapping
floors, areas where the mined flint was worked, are sometimes found within and
around the mine area, along with hearths and traces of timber buildings.
Evidence of secondary uses of abandoned flint mines is fairly common, and
human burials dating from Neolithic times onwards are regularly found in the
upper fills of pits and shafts. The hollows left in the tops of infilled
shafts also provided suitable areas for occupation long after mines themselves
had gone out of use.

The distribution of flint mines is largely dictated by the extent of the Upper
Chalk, which is the geological band in which seams of flint occur. Flint mines
are known in most areas of Upper Chalk outcrops and generally occur on the
tops of hills or ridges, or along their flanking slopes, from Norfolk to
Dorset. The earliest sites, dating to the Early and Middle Neolithic period,
are clustered on the Sussex Downs.

Flint mines are a rare monument type, with only around 20 examples known
nationally. One of relatively few classes of monument dating to all phases of
the Neolithic period, they contain evidence relating to technology and work
organisation in the period and represent the source of the most commonly used
and widespread material available for making edged tools and implements. All
well preserved examples are considered to be of national importance.

The flint mines at Martin's Clump are well preserved examples of their class.
Excavation of one of the shafts has produced a radiocarbon date which is one
of the earliest dates for a Neolithic flint mine in this country. Recent
survey work has indicated that the mining and associated flint working
activity covers an extensive area. The site will contain archaeological
deposits providing information about the Neolithic and Bronze Age flint
industry, economy, environment and society.

The linear boundary which runs past Martin's Clump survives well as an
outstanding example of its class. It represents a form of land division used
from the Middle Bronze Age to the Iron Age period and is now thought to
represent territorial division in an economy in which pastoralism was
predominant. Excavation has enhanced our understanding of this site, dating it
to the Iron Age period.

Bowl barrows, the most numerous form of round barrow, are funerary monuments
dating from the Late Neolithic period to the Late Bronze Age, with most
examples belonging to the period 2400-1500 BC. They were constructed as
earthen or rubble mounds, sometimes ditched, which covered single or multiple
burials. Bowl barrows are particularly representative of their period and a
substantial proportion of surviving examples are considered worthy of
protection.

Associated with the linear boundary at Martin's Clump but earlier in date are
two bowl barrows. Both survive well despite later disturbance. They will
contain archaeological remains providing information about Bronze Age beliefs,
economy and environment.

Source: Historic England

Sources

Books and journals
CDE Conservation Group, , CDE Conservation Group: Archaeological Tour of the CDE Range, (1987), 8-9
Field, D, Barber, M, The Neolithic Flint Mines at Martin's Clump, Overwallop, Hants, (1998)
Clay, R C C, 'Antiquaries Journal' in A Gun-Flint Factory Site In South Wiltshire, , Vol. 5, (1925), 423-6
Fowler, M J F, 'Hampshire Field Club Section Newsletter' in Hampshire gun-flint industries, , Vol. 12, (1989), 24-26
Fowler, M J F, 'Proceedings of the Hampshire Field Club Archaeological Society' in A Gun-Flint Industry At Martin's Clump, Over Wallop, , Vol. 48, (1992), 135-42
Ride, D J, James, D J, 'Proceedings of the Hampshire Field Club Archaeological Society' in An Account of an Excavation of a Prehistoric Flint Mine, , Vol. 45, (1989), 213-15
Ride, D J, 'Proceedings of the Hampshire Field Club Archaeological Society' in The Sectioning of a Linear Feature and Flint Mines, , Vol. In press, (1998)
Stone, J F S, 'Proceedings of the Hampshire Field Club Archaeological Society' in A Flint Mine at Martin's Clump, Over Wallop, , Vol. 12, pt 2, (1933), 177-180

Source: Historic England