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

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

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Latitude: 49.9059 / 49°54'21"N

Longitude: -6.3054 / 6°18'19"W

OS Eastings: 90974.8704

OS Northings: 9522.0504

OS Grid: SV909095

Mapcode National: GBR BXTX.W27

Mapcode Global: VGYC4.NMFH

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

Scheduled Date: 21 January 1999

Source: Historic England

Source ID: 1015669

English Heritage Legacy ID: 15484

County: Isles of Scilly

Civil Parish: St. Mary's

Built-Up Area: Hugh town

Traditional County: Cornwall

Lieutenancy Area (Ceremonial County): Cornwall

Church of England Parish: Isles of Scilly

Church of England Diocese: Truro


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
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.

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.

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

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.

Source: Historic England


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

Title: 1:2500 Ordnance Survey Maps; SV 9009 & SV 9109
Source Date: 1980

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)

Source: Historic England

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