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Two entrance graves and a platform cairn 90m ESE of Basin Rock, Porth Hellick Down, St Mary's

A Scheduled Monument in St. Mary's, Isles of Scilly

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Latitude: 49.9178 / 49°55'3"N

Longitude: -6.2802 / 6°16'48"W

OS Eastings: 92865.803756

OS Northings: 10735.253382

OS Grid: SV928107

Mapcode National: GBR BXWW.VKW

Mapcode Global: VGYC5.3B9D

Entry Name: Two entrance graves and a platform cairn 90m ESE of Basin Rock, Porth Hellick Down, St Mary's

Scheduled Date: 7 October 1976

Last Amended: 17 May 1995

Source: Historic England

Source ID: 1011949

English Heritage Legacy ID: 15366

County: Isles of Scilly

Civil Parish: St. Mary's

Traditional County: Cornwall

Lieutenancy Area (Ceremonial County): Cornwall

Church of England Parish: Isles of Scilly

Church of England Diocese: Truro


The monument includes a close grouping of two prehistoric entrance graves and
a platform cairn situated near the centre of Porth Hellick Down, on
south eastern St Mary's in the Isles of Scilly. The entrance graves and cairn
form a triangular arrangement, the entrance graves being situated 20m apart on
an east-west axis, with the platform cairn 17m NNE of the western entrance
The eastern entrance grave survives with a circular mound of heaped rubble,
15m in diameter and 1m high, built around a large natural granite outcrop, 7m
long, north-south, by 3.5m wide and 1.8m high. The mound rises gently to a
kerb of edge-set slabs, up to 0.6m high, defining a sub-circular central
platform, 9m in diameter. The kerb is noticeably flattened in its north west
sector. The central platform is dominated by the outcrop, slightly east of its
centre, and contains a funerary chamber with a NNW-SSE long axis, utilising
the western face of the outcrop for its eastern side. The chamber is visible
as a turf-covered hollow, 4m long, 1.4m wide and 0.5m deep, defined along its
western side by two edge-set slabs, the largest measuring 1.8m long and 0.5m
high. Two large slabs, called capstones, up to 1.8m long, 0.8m wide and 0.45m
thick, span the chamber's interior, sloping down from the western side-slabs
to the side of the outcrop.
The western entrance grave survives with a circular mound of heaped rubble, 9m
in diameter and 1m high. The mound rises to traces of a kerb of edge-set
slabs, up to 0.9m long and 0.5m high; four slabs are visible, a pair
adjoining in each of the western and north eastern sectors of a kerb
projecting to a total of 5m in diameter. Within the shallow-domed central area
defined by the kerb, an unrecorded antiquarian excavation along the line of
the chamber has produced a hollow extending south from the kerbed area's
northern edge. The hollow measures 2.25m long, north-south, by 1.6m wide and
0.3m deep. Most of the chamber's stone lining has been removed by the
excavation but three granite slabs visible in the turf to the north and south
of the hollow are considered to have been displaced from the chamber's
The platform cairn survives with a circular heather-covered mound of heaped
rubble, 5m in diameter, rising 0.3m to a flattened platform, 3m in diameter.
This monument forms part of a cairn cemetery containing at least six other
cairns dispersed across the central plateau of Porth Hellick Down. The cairns
in this cemetery vary in form but at least six are entrance graves, forming
one of the largest surviving groupings of this type of monument. A broadly
contemporary field system extends along the north west slope of the Down.
Other prehistoric cairn cemeteries, including entrance graves, are located on
the adjacent coastal downs of Salakee Down to the south west and Normandy Down
to the NNE.

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

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'
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.

Entrance graves are funerary and ritual monuments whose construction and use
dates to the later Neolithic, Early and Middle Bronze Age (c.2500 - 1000 BC).
They were constructed with a roughly circular mound of heaped rubble and
earth, up to 25m in diameter, whose perimeter may be defined by a kerb of
edge-set slabs or, occasionally, coursed stone. The mound contains a
rectangular chamber built of edge-set slabs, coursed walling or both, and
covered by large slabs, called capstones, set transversely across the chamber.
The chamber was accessible via a gap in the mound's kerb or outer edge and
often extends back beyond the centre of the mound. The cairn's mound and
chamber may incorporate natural boulders and outcrops. Excavations in entrance
graves have revealed cremated human bone and funerary urns, usually within the
chambers but on occasion within the mound. Unburnt human bone has also
been recovered but is only rarely preserved. Some chambers have also produced
ritual deposits of domestic midden debris, including dark earth typical of the
surface soil found within settlements, animal bone and artefact fragments.
Entrance graves may occur as single monuments or in small or large groups,
often being associated with other cairn types in cemeteries. They may also
occur in close proximity to broadly contemporary field boundaries.
The national distribution of entrance graves is heavily weighted towards the
Isles of Scilly which contain 79 of the 93 surviving examples recorded
nationally, the remaining 14 being located in western Cornwall.
Platform cairns are also funerary monuments, of Early Bronze Age date (c.2000
- 1600 BC). They were constructed as low flat-topped mounds of stone rubble,
up to 40m in external diameter though usually considerably smaller, covering
single or multiple burials. Some examples have other features, including
peripheral banks and internal mounds constructed on the platform. A kerb of
slabs or edge-set stones sometimes bounds the edge of the platform, and a
peripheral bank or mound if present. As with entrance graves, platform cairns
can occur as isolated monuments, in small groups or in cairn cemeteries. In
cemeteries they are normally found alongside cairns of other types.
Platform cairns form a significant proportion of the 387 surviving cairns on
the Isles of Scilly; this is unusual in comparison with the mainland.
The considerable variation in form, the longevity and the associations both of
platform cairns and the nationally rare entrance graves provide important
information on the diversity of beliefs, burial practices and social
organisation in the Bronze Age.
The two entrance graves and the platform cairn forming this grouping on Porth
Hellick Down have survived well, despite the attentions of early antiquaries
on the western entrance grave. The incorporation of natural outcrops into the
funerary mound is a feature found elsewhere on the Isles of Scilly but which
is unusual and rare nationally. The varied funerary structures contained in
this monument and their proximity to the other broadly contemporary and
diverse cairns on Porth Hellick Down demonstrates the diversity of funerary
practices during the Bronze Age. The proximity of these cairns to a
prehistoric field system on the western slope of the Down and the disposition
of this and the other cairn cemeteries on successive downs along the coast
illustrates well the organisation of land use among prehistoric communities.

Source: Historic England


Books and journals
Ashbee, P, Ancient Scilly, (1974)
Ashbee, P, Ancient Scilly, (1974)
Ashbee, P, Ancient Scilly, (1974)
Ashbee, P, The chambered Tombs on St Mary's, Isles of Scilly, (1963), 9-18
Ashbee, P, The chambered Tombs on St Mary's, Isles of Scilly, (1963), 9-18
Russell, V, Isles of Scilly Survey, (1980)
Russell, V, Isles of Scilly Survey, (1980)
Russell, V, Isles of Scilly Survey, (1980)
consulted 1994, Waters, A., AM 107 for Scilly SMR entry PRN 7527, (1988)
consulted 1994, Waters, A., AM 107 for Scilly SMR entry PRN 7528, (1988)
consulted 1994, Waters, A., AM 107 for Scilly SMR entry PRN 7528.02, (1988)
consulted 1994, Waters, A., AM 107 for Scilly SMR entry PRN 7528.03, (1988)
consulted 1994, Waters, A., AM 107 for Scilly SMR entry PRN 7528.11, (1988)
Rees, S., AM7 scheduling documentation for CO 1026, 1975, consulted 1994
Rees, S., AM7 scheduling documentation for CO 1026, 1975, part 'a'. Consulted 1994
Title: 1:2500 Ordnance Survey Map; SV 9210
Source Date: 1980

Source: Historic England

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