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Prehistoric linear boundary south east of Horse Rock on Porth Hellick Down, St Mary's

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

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Latitude: 49.9183 / 49°55'5"N

Longitude: -6.2784 / 6°16'42"W

OS Eastings: 92992.083283

OS Northings: 10792.528068

OS Grid: SV929107

Mapcode National: GBR BXWW.WH1

Mapcode Global: VGYC5.496Y

Entry Name: Prehistoric linear boundary south east of Horse Rock on Porth Hellick Down, St Mary's

Scheduled Date: 16 November 1998

Source: Historic England

Source ID: 1013668

English Heritage Legacy ID: 15412

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 linear boundary crossing the eastern slope
of Porth Hellick Down on the south east coast of St Mary's in the Isles of
The linear boundary survives as an almost straight line of small upright slabs
and boulders, up to 0.5m high and 1.5m to 6m apart, which extends south east -
north west for 17m from the eastern edge of the Down, and is then continued
for a further 23m on the same course by traces of a rubble bank, up to 1m
wide, 0.1m high and largely blanketed by the heather turf. The boundary is
aligned to the north west on a prominent natural granite outcrop called Horse
Rock and ends as a visible feature 10m before reaching that outcrop.
The monument is located near a number of other broadly contemporary features
on Porth Hellick Down: a prehistoric field system extends across the northern
and north western parts of the Down, from 55m west of this monument, while
across the centre of the Down is a large and diverse group of prehistoric
funerary cairns, including the largest surviving cemetery of entrance graves,
from 112m south-west of this monument.

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 on the Isles of Scilly were constructed from the
Bronze Age to the early medieval period (c.2000 BC-AD 1066): closer dating
within that period may be provided by their visible relationships to other
classes of monument, or by their relationship with an earlier recorded sea
level. They consist of stone walls, up to 3m wide and 1.1m high but usually
much slighter, and are formed of heaped rubble, often incorporating edge- or
end-set slabs called orthostats.
Linear boundaries served a variety of functions. These included separating
land regularly cultivated from that less intensively used, separating land
held by different social groups, or delineating areas set aside for
ceremonial, religious and funerary activities. Linear boundaries are often
associated with other forms of contemporary field system. The Isles of Scilly
contain examples of an associaton, rarely encountered elswhere, whereby
certain linear boundaries directly link several cairns, entrance graves and
cists in some groups of prehistoric funerary monuments.
Linear boundaries along the coastal margin of the islands are often
indistinguishable from the truncated upper walls of early field systems whose
remaining extent has been destroyed by the rising sea level. Linear boundaries
form a substantial part of the evidence of early field systems recorded on the
Isles of Scilly. They provide significant insights into the physical and
social organisation of past landscapes and form an important element in the
existing landscape. Even where truncated by the rising sea level, their
surviving lengths provide important evidence for the wider contemporary
context within which other nationally important monuments at higher altitudes
were constructed. A substantial proportion of surviving examples are
considered worthy of protection.

This linear boundary on Porth Hellick Down has survived well. Its alignment on
Horse Rock and its confinement to the coastal slope shows clearly the
influence of natural features on the organisation of the landscape during the
prehistoric period. Its proximity to other surviving prehistoric field systems
and funerary monuments on Porth Hellick Down demonstrates the manner of that
organisation and the relationship between farming and religious activities
amongst prehistoric communities.

Source: Historic England


consulted 1994, CAU, AM 107 for Scilly SMR entry PRN 7527, (1988)
consulted 1994, CAU, AM 107 for Scilly SMR entry PRN 7528, (1988)
Title: 1:2500 Ordnance Survey Map, SV 8715
Source Date: 1980

Source: Historic England

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