Martin Down style enclosure, bowl barrow, Iron Age hillfort, Romano-British village and associated field system on Thundersbarrow Hill


Heritage Category:
Scheduled Monument
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The building or site itself may lie within the boundary of more than one authority.

West Sussex
Adur (District Authority)
West Sussex
Horsham (District Authority)
Upper Beeding
National Park:
National Grid Reference:
TQ 22985 08218

Reasons for Designation

Martin Down enclosures (named after a typical example on Martin Down in Dorset), are small, usually sub-rectangular areas often covering less than 0.3ha. originally bounded by a low bank and/or fence with a surrounding ditch. Most have a single entrance, identified by a causeway over the ditch. Dating to the Late Bronze Age, from the tenth to eighth centuries BC, these enclosures are interpreted as domestic settlements, and excavated examples have been found to contain circular structures, post holes, pits, hollows and burnt mounds, associated with fragments of querns, pottery, animal bones, charred grain, worked flint artefacts and metalwork. In some cases, as with the enclosure on Martin Down itself, they are associated with contemporary field systems. They occur mainly on the chalk downland of central southern England, although examples in Kent, Sussex, East Anglia and the Midlands are also known. Generally constructed on the flanks of hills, they have also been identied in valley bottoms and on hilltops. Because they are usually situated on good agricultural land, many have been levelled by subsequent ploughing and survive largely in buried form, often visible as cropmarks on aerial photographs. Fewer than 15 examples have been positively identified so far. Martin Down enclosures are thus a very rare monument type and form one of a limited range of monuments dating to the Late Bronze Age. All examples with surviving remains are considered to merit protection.

The Martin Down style enclosure on Thundersbarrow Hill survives comparatively well, despite some damage caused by ploughing. Part excavation has shown that it contains information about the landscape in which it was constructed and about its contemporary and later use. The later hillfort also survives comparatively well, and its close association with the earlier enclosure illustrates the frequent utilisation of hillfort locations in the earlier prehistoric periods. Also commonly found on hilltop locations are bowl barrows, a type of Bronze Age burial mound. The environs of the hillfort have also been investigated by part excavation and survey, revealing an area of later Roman settlement and an associated field system. Together these remains illustrate the changing function of the hilltop over nearly two millennia.


The monument includes a Martin Down style enclosure and bowl barrow dating to the Bronze Age, a later slight univallate hillfort dating to the Iron Age and a Romano-British aggregate village and associated regular aggregate field system, situated on a north west-south east aligned chalk ridge which forms part of the Sussex Downs. Also included within the monument are traces of medieval strip cultivation, a 19th century dewpond and a group of slit trenches associated with the use of the ridge as an army training area during World War I and World War II. Lying near the north western edge of the monument, within the later hillfort, the Martin Down style enclosure covers an area of c.0.49ha. Part excavation in 1985 and earlier records suggest that the roughly square enclosure, which has sides measuring c.70m, has been largely levelled by modern ploughing but survives as a slightly raised area originally bounded by a low bank. This is surrounded by a now infilled ditch which survives as a buried feature c.3m wide and c.0.6m deep. Two original entrances have been identified, formed by c.6m wide gaps through the western and eastern defences. The excavation also led to the discovery of fragments of bone, worked flints, a piece of antler and pottery sherds in the ditch fills, and analysis of the latter has suggested that the enclosure was in use during the tenth and ninth centuries BC. The enclosure is associated with a broadly contemporary, now infilled, north-south aligned ditch situated c.18m to the west. This is c.4.5m wide and partly underlies the north western ramparts of the later hillfort. The roughly circular hillfort has also been partly levelled by modern ploughing and survives to the east largely in buried form, with some features visible as crop marks on aerial photographs. To the west, the defences, which enclose an area of c.1.33ha, are formed by a bank surviving as a scarp up to c.1m high. Part excavation in 1932 showed that this is surrounded by a now infilled ditch c.7m wide. Access to the interior is provided by two entrances through the northern and south eastern ramparts. The northern entrance is formed by a simple gap c.18m wide, whilst the south eastern entrance has an inturned passageway c.9m wide. Pottery found during the excavation suggests that the hillfort was constructed during the sixth century BC and continued in use until the mid-third century BC. Despite some later disturbance by 20th century army training activities and modern ploughing, the hillfort interior will contain further buried remains relating to the use of the hillfort and the earlier underlying Martin Down style enclosure. The bowl barrow, known as Thunders Barrow, lies c.10m south east of the later hillfort. The south eastern side of the barrow was disturbed by the construction of the adjacent dewpond in 1873, which led to the discovery of human cremation burials contained within pottery cinerary urns dating to the prehistoric, Roman and early medieval periods. The barrow was also partly disturbed by earth moving in 1964. It survives as a semi-circular mound c.17m in diameter and up to c.2m high. The later Romano-British village lies in the areas to the east and north of the hillfort, and its structures have also partly disturbed the hillfort ramparts. The village now survives in buried form, and topographical survey and part excavation in 1932 identified the focus of the village as two adjacent roughly square platforms with sides measuring c.30m, containing a number of rectangular houses c.5m by c.3.5m. Pottery sherds and coins dating to the years between c.50-400 AD suggest that the village was inhabited for most of the period of the Roman occupation. Associated with the houses are a well, a number of storage pits and two furnaces, interpreted as corn drying ovens, one of which is situated c.70m to the north of the focus of the village. The excavations also revealed fragments of daub, part of a sandstone rotary quern and charred wheat grains. Further buried remains associated with the use of the ridge at this time will survive in the areas between and around these features. The agricultural activities practiced by the inhabitants of the village are represented by the contemporary field system which survives on the hillslopes which form the southern, western and eastern sides of the ridge. This covers an area of c.40ha. A series of lynchets, which survive as earthworks up to c.0.5m high and as crop marks visible on aerial photographs, define the individual fields, which are mainly rectangular, with an average size of c.0.35ha. At least two associated trackways have been identified, with the main route running along the ridge just to the south west of the modern downland track which traverses the monument. Military trenches excavated during World War One on the south western slopes and traces of medieval cultivation, which range down the hillslope to the east of the Romano-British village, have partly disturbed the field system. Analysis of soil samples from the fields has indicated that the hillsides were also being cultivated during the earlier Iron Age period. The modern fences and the surface of the modern trackway which cross the monument 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.


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

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Books and journals
Curwen, E C, 'Antiquaries Journal' in Excavations on Thundersbarrow Hill, Sussex, (1933), 109-151
Curwen, E C, 'Antiquaries Journal' in Excavations on Thundersbarrow Hill, Sussex, (1933), 109-151
Rudling, D, Thundersbarrow Hill: Plough Damage Assessment Report, 1985, unpublished report for EH
Thompson, S, Lynchet Formation and Land-Use: Thundersbarrow Hill, 1986, unpublished BSC dissertation
Thompson, Samantha , Lynchet Formation and Land-Use: Thundersbarrow Hill, 1986, unpublished BSC dissertation


This monument is scheduled under the Ancient Monuments and Archaeological Areas Act 1979 as amended as it appears to the Secretary of State to be of national importance. This entry is a copy, the original is held by the Department for Digital, Culture, Media and Sport.

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