Prehistoric cairn group and field systems on Great Arthur, St Martin's


Heritage Category: Scheduled Monument

List Entry Number: 1018616

Date first listed: 07-Oct-1976

Date of most recent amendment: 21-Jan-1999


Ordnance survey map of Prehistoric cairn group and field systems on Great Arthur, St Martin'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. Martin's

National Grid Reference: SV 94183 13508


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.

A variety of prehistoric funerary monuments survives on Scilly, with a combined date range extending from the later Neolithic to the Middle Bronze Age (c.2500-1000 BC). Most are formed as funerary cairns constructed as earth-and-rubble mounds, with flattened tops in the case of platform cairns and entrance graves, often with a kerb of stones or edge-set slabs around the mound, platform surface or both. In round and platform cairns, burials were sometimes accompanied by pottery urns and placed on the old land surface, in small pits or, on occasion, within a box-like structure of slabs called a cist which may also be set into the old ground surface or dug into the body of the cairn. Occasionally, cairns include larger stone-built funerary chambers, built of edge-set slabs, coursed rubble walling or both, and roofed by large covering slabs; the chamber may be closed or, in the case of entrance graves, accessible via a gap in the mound's kerb or outer edge. Each of these forms of funerary monument can occur singly, in small groups or in larger cemeteries containing several types. They may also occur in close proximity to prehistoric field systems and linear boundaries, displaying relationships of considerable significance for our understanding of the development of land use, funerary practice and settlement during the prehistoric and later periods. The field systems so associated may be of various forms, irregular or regular and enclose large or small plots. The diversity of overall pattern and detail displayed by these field systems provides valuable insights into the physical and social organisation of past landscapes. The prehistoric funerary and settlement elements on Great Arthur survive well, including a direct physical association between the cairns and a field system. The diversity of form present among the cairns and the linear arrangement of the cairn group on the island's ridge give useful insights into the nature of prehistoric funerary ritual and the important influence of topography on its physical expression. The influence of underlying landforms is also clearly apparent in the layout of the field systems, their boundary orientations generally varying with the slope while several of their delimiting boundaries follow the crests of the island's main ridge and spurs. The field system survivals are sufficiently extensive to show the pattern of land division employed and the deep lynchetting will preserve important old land surfaces, deposits and features. Although confined to an island by rising sea levels, the funerary and settlement remains on Great Arthur complement those on the nearby islands to preserve valuable evidence for the nature and development of land use in the now largely submerged prehistoric and Roman landscape in the east of the Scilly archipeligo.


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


The monument includes a group of seven prehistoric funerary cairns with adjacent prehistoric field systems on Great Arthur, a small uninhabited island in the Eastern Isles of the Isles of Scilly. The cairn group extends as a line over 80m of the island's north east-south west summit ridge. The north eastern cairn, on raised ground at the end of the ridge, is a large entrance grave. Two large chambered cairns are similarly sited on higher ground at the south west end of the group. The ridge between contains four smaller kerbed platform cairns. All of the cairns are linked by a wall of a prehistoric field system. The north eastern entrance grave has a sub-circular mound to 14m in diameter, rising 1.9m to a flattened top 6m in diameter. A kerb of spaced slabs and boulders is visible near the foot of the mound. A second kerb bounds the upper surface and is exposed on the south as a coursed slab wall 0.7m high. The upper surface contains a subrectangular funerary chamber, 3.6m long, NNE-SSW, by up to 1.5m wide and 0.7m deep internally, its west side convex. The sides are walled by at least three courses of laid slabs, with an edge-set slab closing the southern end. The north end lacks visible closure and a slight depression in the mound beyond is considered to be the chamber entrance. Three covering slabs, to 2m long, cross the chamber, one at the south and two adjacent across the northern half. The north eastern of the two large cairns at the south west of the ridge has a mound 10m in diameter, rising 1.7m to a flattened top 6m in diameter; a perimeter kerb of large slabs is visible on most sides. Its upper surface contains traces of a funerary chamber, visible as an ovoid hollow 4.5m long, north-south, by 3.5m wide and 0.7m deep. The south western cairn in the group has a mound 12m in diameter and up to 1.4m high, incorporating the upper rocks of a natural knoll whose sides drop steeply from the west of the cairn. It has a flattened upper surface 6m long, east-west, by 4.5m wide, with indications of a funerary chamber visible in the north west sector as an ovoid hollow 3m long, north east-south west, by 2m wide and 0.2m deep; four stones, to 0.2m high, are spaced around its edge. This cairn is on the island's highest point, marked by a disused Admiralty triangulation point which now survives as a small modern rubble mound, 0.5m high, on the north east of the cairn's upper surface. The other four cairns in the group are spaced 0.5m to 4.5m apart along the ridge between the larger cairns at each end. Each adjoins the prehistoric wall following the spine of the ridge and they are located alternately on one side of the wall then the other, the south western of these small cairns being on the south east side of the wall. They share similar forms, with rounded mounds in the range 4m-6.5m in diameter, built out from the slope to 0.25m-0.6m high on the downslope edges. The mounds have flattened upper platforms, 3m-4.2m in diameter, defined by small kerb slabs which form a continuous kerb in the south western of the cairns but which are spaced in the other three. In each cairn, the curve of its mound, kerb and platform is truncated by the line of the prehistoric wall. The wall linking the cairn group forms part of a prehistoric field system, one of two that subdivide much of the island's land area. The field systems' plots and linear boundaries are defined by boulder and rubble banks, usually turf covered and generally 1m-2m wide by 0.5m high, frequently incorporating end- set slabs called orthostats, 0.2m-1m high, spaced 1m-3m apart along their midline. Where they roughly follow the contour the banks appear as substantial steps in the slope profile called lynchets, up to 1m high, whose deposits often mask their orthostats and whose form reflects soil movement against and from the original boundaries due to early cultivation on the slope. On the island's north flank, a row of three rectangular plots is defined by four banks running upslope from the present coastal edge to end on a large lynchet at approximately the 10m contour level. This field system is continued west by another bank extending the line of the lynchet across the lower slope of the island's north western spur, linking the main hill with a small knoll at its north west tip. From outcrops on that spur's midslope, another boundary runs extends WNW down the foot of the steep western slope, a remnant of field system otherwise truncated by the island's submergence. A higher level boundary survives along the upper spine of the north western spur, curving south as it meets the summit ridge to merge with the base of the south western cairn. The prehistoric wall linking the cairns along the summit ridge is the north western of at least three roughly parallel north east-south west boundaries in another field system across the island's south east flank, its lower boundaries being heavily lynchetted. The area is divided into rectangular plots by at least three walls running downslope, north west-south east: two descend to the present coastal edge; the third, on the south west, runs along a spur extending SSE from the island's summit ridge and links the ends of the north east-south west boundaries. The course of this south western boundary undergoes a distinct stagger as it passes each north east-south west boundary, indicating it was secondary in laying out the field system; at its south east end this boundary is angled to the south west to terminate on a natural outcrop. In addition to the field systems, shell midden deposits have also been recorded from the north east coast of the island and from Arthur Head, on the island's southern tip. Beyond this scheduling, broadly contemporary cairn groups and settlement remains survive on several other islands of the Eastern Isles, including Middle Arthur and Little Arthur which, with Great Arthur, are now joined by inter-tidal bars; further field boundaries and house platforms occur on Little Ganilly nearby to the north. These survivals, now separated by the sea, were linked by dry land in the landscape contemporary with their construction when the Eastern Isles formed areas of high ground in the dissected terrain of a single broad peninsula.

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: 15489

Legacy System: RSM


Books and journals
Russell, V, Isles of Scilly Survey, (1980)
Thomas, C, Exploration of a Drowned Landscape, (1986)
Thomas, C, Exploration of a Drowned Landscape, (1986)
Cairn SV 91 SW 6D, Quinnell, N V, Ordnance Survey Record & Illustration Cards for SV 91 SW 6, (1978)
Cairn SV 91 SW 6E, Quinnell, N V, Ordnance Survey Record & Illustration Cards for SV 91 SW 6, (1978)
Consulted 1996, CAU, Scilly SMR entry PRN 7220,
Consulted 1996, CAU, Scilly SMR entry PRN 7228,
Quinnell, N V, Ordnance Survey Record Card and Illustration for SV 91 SW 6A, (1978)
Slide 7/688 in ADH slide collection, Hooley, A D, Air photo of the Arthurs taken from south on 23/3/1996, (1996)
Thorpe, C, AM 107 for Scilly SMR entry PRN 7222, (1988)
Thorpe, C/CAU, AM 107 for Scilly SMR entry PRN 7221.01, (1988)
Thorpe, C/CAU, AM 107 for Scilly SMR entry PRN 7221.02, (1988)
Thorpe, C/CAU, AM 107 for Scilly SMR entry PRN 7221.03, (1988)
Thorpe, C/CAU, AM 107 for Scilly SMR entry PRN 7221.04, (1988)
Thorpe, C/CAU, AM 107 for Scilly SMR entry PRN 7221.05, (1988)
Thorpe, C/CAU, AM 107 for Scilly SMR entry PRN 7222, (1988)
Thorpe, C/CAU, AM 107s for Scilly SMR entries for PRN 7221.04-.05, (1988)
Thorpe, C/CAU, AM 107s for Scilly SMR entries PRN 7221.04-.05, (1988)
Title: 1:10000 Ordnance Survey Map; SV 91 SW Source Date: 1980 Author: Publisher: Surveyor:
Title: Ordnance Survey Record & Illustration Cards for SV 91 SW 6 Source Date: 1978 Author: Publisher: Surveyor:

End of official listing