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Prehistoric house platform and boundary north east of Carn Leh, St Mary's

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

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Latitude: 49.9094 / 49°54'34"N

Longitude: -6.3012 / 6°18'4"W

OS Eastings: 91305.602644

OS Northings: 9898.433483

OS Grid: SV913098

Mapcode National: GBR BXTX.QKY

Mapcode Global: VGYC4.QJPS

Entry Name: Prehistoric house platform and boundary north east of Carn Leh, St Mary's

Scheduled Date: 21 January 1999

Source: Historic England

Source ID: 1015670

English Heritage Legacy ID: 15485

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 prehistoric house platform and adjacent linear
boundary on the north eastern coastal margin of Carn Leh, a prominent natural
outcrop at the south west of the entrance to Old Town Bay on the south coast
of St Mary's in the Isles of Scilly.
The house platform is visible as a sub-circular hollow with a 4.2m diameter
flattened base sloping slightly to the north east and levelled into the
steeper north eastern slope close to the base of the Carn Leh outcrop. The
levelling produces a steep backscarp, to 0.5m high, along the south west of
the platform; rubble facing is detectable through the turf covering the
backscarp, changing to a wall of at least five slabs in line, extending 2.8m
along the north west of the platform and ending on the north at a large
boulder, 1m long and 0.7m high. On the north east, the interior is defined by
a very slight raised bank, 0.3m wide and 0.2m high, behind the present coastal
From the platform's north western walling, the adjacent linear boundary
extends north west then curves to the north before being truncated by this
present coastal cliff to give a surviving length of 9m. The boundary is
visible as a turf-covered bank generally 1.5m wide and 0.4m high, with its
rubble fabric exposed where it runs into the cliff edge.
Beyond this scheduling the walls and banks of a prehistoric field system
extend along the eastern flank of Peninnis Head from 230m to the south west,
with a prehistoric cairn cemetery on the higher land of that promontory.
Beyond the south of this scheduling is the much later embanked defended area
of a Civil War gun battery on the south eastern coastal margin of Carn Leh.

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.
Both linear boundaries and house platforms provide significant insights into
the physical and social organisation of past landscapes.
This house platform beside Carn Leh survives well. Despite truncation of the
adjacent boundary by coastal encroachment, both the house platform and
boundary provide evidence for the presence and nature of early land use in an
area now largely submerged by rising sea levels. Their survival at such a low
level complements the patterns of broadly contemporary field system and cairn
cemetery survivals on the higher land of Peninnis Head and thereby contributes
to our wider view of land use and settlement organisation among prehistoric
communities in the pre-submergence landscape of Scilly.

Source: Historic England


Parkes, C & Herring, P, Scilly SMR entry PRN 7709, (1990)
Parkes, C & Herring, P/CAU, Scilly SMR entry PRN 7709, (1990)
Title: 1:2500 Ordnance Survey Map; SV 9109
Source Date: 1980

Source: Historic England

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