Prehistoric linear boundaries, house platform and cairn on south western Peninnis Head, St Mary's


Heritage Category: Scheduled Monument

List Entry Number: 1015669

Date first listed: 21-Jan-1999


Ordnance survey map of Prehistoric linear boundaries, house platform and cairn on south western Peninnis Head, St Mary's
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The building or site itself may lie within the boundary of more than one authority.

District: Isles of Scilly (Unitary Authority)

Parish: St. Mary's

National Grid Reference: SV 90851 09754, SV 90890 09739, SV 90974 09526


Legacy Record - This information may be included in the List Entry Details.

Reasons for Designation

The Isles of Scilly, the westernmost of the granite masses of south west England, contain a remarkable abundance and variety of archaeological remains from over 4000 years of human activity. The remote physical setting of the islands, over 40km beyond the mainland in the approaches to the English Channel, has lent a distinctive character to those remains, producing many unusual features important for our broader understanding of the social development of early communities. Throughout the human occupation there has been a gradual submergence of the islands' land area, providing a stimulus to change in the environment and its exploitation. This process has produced evidence for responses to such change against an independent time-scale, promoting integrated studies of archaeological, environmental and linguistic aspects of the islands' settlement. The islands' archaeological remains demonstrate clearly the gradually expanding size and range of contacts of their communities. By the post- medieval period (from AD 1540), the islands occupied a nationally strategic location, resulting in an important concentration of defensive works reflecting the development of fortification methods and technology from the mid 16th to the 20th centuries. An important and unusual range of post- medieval monuments also reflects the islands' position as a formidable hazard for the nation's shipping in the western approaches. The exceptional preservation of the archaeological remains on the islands has long been recognised, producing an unusually full and detailed body of documentation, including several recent surveys.

The early linear boundaries of the Isles of Scilly were constructed from the Bronze Age to the early medieval period (c.2000 BC to AD 1066): closer dating within that period may be provided by their visible relationships to other classes of monument or by their relationship to an earlier recorded sea level. They consist of stone walls, up to 3m wide and 1.1m high but usually much slighter and sometimes covered by later deposits. They served a variety of functions including: separating land regularly cultivated from that less intensively used; separating land held by different social groups; or delineating areas set aside for ceremonial or religious activity. Linear boundaries on the coastal margin of the islands are often indistinguishable from truncated upper walls of early field systems, the rest of whose extent has been destroyed by the rising sea level. As one element within wider systems of landscape subdivision, linear boundaries may have a close physical relationship to contemporary settlement sites including house platforms: rounded or polygonal areas levelled into a slope and with interiors defined by the levelling backscarp, sometimes faced with stone, and often with a bank along the perimeter of the forward edge. Excavations have shown that some house platforms supported timber and stone built houses whose post holes, lower courses and occupation surfaces are masked beneath later deposits. Their relationships with datable field systems and finds from excavations indicate that house platforms were constructed over a similar period to linear boundaries. The Isles of Scilly contain also examples of an association rarely encountered elsewhere, whereby some linear boundaries are orientated on, and sometimes directly link, funerary monuments in some prehistoric cemeteries. Platform cairns are one such class of funerary monument, constructed as low flat-topped mounds of rubble, up to 40m in diameter but usually considerably smaller, covering single or multiple burials. Some examples have other features, including perpheral banks and an internal mound built on the platform, with slab-kerbing bounding the edge of the mound. Platform cairns form a high proportion of the 387 surviving cairns recorded on the Isles of Scilly. Linear boundaries, house platforms and platform cairns provide significant insights into the physical and social organisation of past landscapes. Where closely associated, they give important evidence for developing relationships between settlement, agricultural and religious activity among prehistoric communities.

The early linear boundaries on the south west flank of Peninnis Head, together with the adjacent house platform and cairn, survive reasonably well despite limited effects of stone-working and visitor trample at the house platform and cairn respectively. The features in this scheduling form an integral part of an extensive range of surviving prehistoric monuments on Peninnis Head, complementing the early field systems and cairn cemetery on the south and east of the promontory and the settlement exposed along its north west coast. This scheduling thereby contributes to our wider view of land use and settlement organisation among early communities in the pre-submergence landscape of Scilly. The disposition of the boundaries also highlights the important influence of natural features on the detail of early land division. The substantial lynchetting evident along much of the boundaries' courses will also preserve archaeological and environmental data contemporary with and subsequent to their construction.


Legacy Record - This information may be included in the List Entry Details.


The monument, which is divided into three areas of protection, includes three prehistoric linear boundaries crossing the south west flank of Peninnis Head, a broad promontory on the south coast of St Mary's in the Isles of Scilly. The monument also includes a prehistoric platform cairn beside the central boundary and a house platform adjacent to the south eastern boundary. The linear boundaries form the western elements of wider prehistoric land division on Peninnis Head, where prehistoric field system remains survive on its south and eastern flanks. Rather than creating a network of plots the three boundaries in this scheduling form more widely-spaced subdivisions, strongly influenced by local landforms on the promontory's steep south west flank. The north western and the south eastern boundaries in the scheduling are approximately 300m apart following NNE-SSW courses across the western flanks of successive spurs linking the spine of Peninnis Head with the craggy headlands of Carn Mahael and Dutchman's Carn. The third boundary survives along part of the crest of the spur leading to Carn Mahael. The boundaries survive as rubble banks with occasional edge-set slabs and traces of coursed facing visible along their sides but they are usually partly or wholly blanketted by later deposits, especially where they follow the contour, giving them the appearance of soil-covered steps, called lynchets, crossing the slope. The north west boundary extends over at least 130m, strongly lynchetted for most of its length; it is generally 2.5m wide with a downslope scarp 0.75m high but its northern half is wider and lower, spread by modern improvement in the pasture fields through which it passes. At the south, reduced lynchetting leaves the southern 10m of the boundary as a more distinct earth and rubble bank with larger blocks, to 0.8m high, forming a western face and with a curve to the west before it terminates on a natural line of outcrops along the midslope of the Carn Mahael spur. The central of the three boundaries survives over at least 22m north east- south west along the spine of the Carn Mahael spur from the limit of modern enclosure at the base of the spur on the north east. The boundary is aligned south westward on the granite outcrops forming Carn Mahael itself. It survives as a low rubble bank, 0.75m wide and 0.1m high, fading as a visible feature before reaching the Carn outcrops. Immediately south east of the boundary's surviving north east end is a prehistoric platform cairn, visible as a low sub-circular mound, 10m in diameter, whose flattened top rises 0.3m along its south west edge and whose rubble content is exposed by a path running north west-south east across its surface. The south eastern boundary survives over at least 97m along the midslope of a broad spur behind Dutchman's Carn from below the crest of the promontory to the north east. It is generally 1.5m-2.5m wide, 0.25m high on its upslope side and 0.75m high to downslope; a downslope facing of laid and edge-set slabs, to 0.6m high, is visible near the boundary's midpoint. As it approaches the Carn at the south west, the boundary curves south, rising to the spine of the spur, then bends west to terminate as a 12.5m long row of closely-spaced edge-set slabs and boulders, to 0.75m high and 0.7m wide, running to the base of the tall natural outcrop of Dutchman's Carn. Near the centre of the boundary, a short bank branches northwards to join the south side of a house platform. The house platform has a sub-triangular interior levelled into the subsoil of the steep slope and measuring 7.5m along its north west side by 4.5m from the north west to the south east apex. Its levelling backscarp on the east and south rises to 0.9m high, faced largely by earth and subsoil and accompanied by a slight bank outside the scarp on the east. The north west side, facing downslope, is defined by a massive bank, to approximately 4m wide, only 0.25m above the interior but descending 1.8m to the lower external surface. An entrance gap 1.8m wide occurs at the north east apex. The interior of the house platform contains two small slabs with drilled splitting-marks along their edges; these indicate limited reuse after c.AD 1800 when that splitting method was introduced, testing the site's quarrying potential as an outlier to extensive quarrying activity visible to the south on this spur. Beyond this scheduling, prehistoric field systems on Peninnis Head extend from 165m north east and 190m south east of the south eastern linear boundary, while prehistoric cairns of a cairn cemetery on higher land near the tip of the promontory occur from 37m north east of that same boundary. Settlement features dating to the Middle and Later Bronze Age occur in the promontory's north western coastal cliff, from 250m north west of this scheduling.

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: 15484

Legacy System: RSM


Books and journals
Ashbee, P, Ancient Scilly, (1974)
Ashbee, P, Ancient Scilly, (1974)
Ratcliffe, J , Straker, V, The Early Environment of Scilly, (1996)
Gerrard, S., English Heritage Book of Dartmoor, 1997, Forthcoming
Gerrard, S., English Heritage Book of Dartmoor, 1997, Forthcoming
Parkes, C/CAU, AM 107s for Scilly SMR entries PRN 7152 & 7636, (1988)
Title: 1:2500 Ordnance Survey Maps; SV 9009 & 9109 Source Date: 1980 Author: Publisher: Surveyor:
Title: 1:2500 Ordnance Survey Maps; SV 9009 & SV 9109 Source Date: 1980 Author: Publisher: Surveyor:
Waters, A/CAU, AM 107 for Scilly SMR entry PRN 7419, (1988)
Waters, A/CAU, AM 107 for Scilly SMR entry PRN 7420, (1988)
Waters, A/CAU, AM 107 for Scilly SMR entry PRN 7581, (1988)

End of official listing