Flint mines, linear boundary and two bowl barrows at Martin's Clump, Porton Down


Heritage Category: Scheduled Monument

List Entry Number: 1017168

Date first listed: 08-Jan-1971

Date of most recent amendment: 09-Feb-2001


Ordnance survey map of Flint mines, linear boundary and two bowl barrows at Martin's Clump, Porton Down
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The building or site itself may lie within the boundary of more than one authority.

County: Hampshire

District: Test Valley (District Authority)

Parish: Over Wallop

National Grid Reference: SU 25001 38715


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Reasons for Designation

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.


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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.


The contents of this record have been generated from a legacy data system.

Legacy System number: 26787

Legacy System: RSM


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

End of official listing