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.
Regular field systems are one of several methods of field layout known to have
been employed in the Isles of Scilly from the Bronze Age to the Roman period
(c.2000 BC - AD 400); closer dating within that period may be provided by the
visible relationships of the field boundaries to other classes of monument
with a shorter known time-span of use, or by their relationship with an
earlier recorded sea level.
They comprise a collection of field plots defined by boundaries laid out in a
consistent manner, along two dominant axes at approximate right angles to each
other. This results in rectilinear fields which may vary in their size and
length:width ratio both within and between individual field systems. The
fields are bounded by rubble walls or banks, often incorporating edge- or end-
set slabs called orthostats. Within its total area, a regular field system may
be subdivided into blocks differing in the orientations of their dominant
axes.
Regular field systems may be associated with broadly contemporary settlement
sites such as stone hut circles. Some regular field systems on the Isles of
Scilly contain a distinctive association, rarely encountered elsewhere,
whereby certain of their field boundaries directly incorporate or link cairns,
entrance graves and cists in some groups of prehistoric funerary monuments.
Although no precise figure is available, regular field systems form one of the
three principal forms of prehistoric field system, along with irregular field
systems and some groups of prehistoric linear boundaries, which survive in
over 70 areas of the Isles of Scilly. They provide significant insights into
the physical and social organisation of past landscapes and they provide
evidence for the wider contemporary context within which other nationally
important monuments were constructed.
The layout of this field system on Heathy Hill survives well, clearly
displaying the character of the prehistoric land division and the strong
influence upon it of the natural topography. Despite truncation by rising sea
levels, the field system contains a sufficient range of elements to determine
its nature, extent and the arrangement of contemporary settlement sites within
it. Its proximity to the complementary inter-tidal field system remains in
Great Porth permits an unusually broad view of prehistoric land allotment
across an altitude range extending into those now-submerged levels. The wider
prehistoric land use context of this monument and its relationship to funerary
and ritual activity is demonstrated by the prehistoric field systems and cairn
cemeteries on Samson Hill and Gweal Hill. The kelp pit contained in this
monument also survives well. As one of only about a dozen surviving kelp pits,
its form and coastal location are typical and its association with the
abandoned quay in Great Porth illustrates the main visible elements of this
former major activity in the islands' economy.
Details
The monument includes a prehistoric field system extending over most of the
slender promontory of Heathy Hill on the south west coast of Bryher in the
Isles of Scilly. The field system incorporates a broadly contemporary hut
circle settlement and at the northern edge of the monument it incorporates a
kelp pit used for soda ash manufacture during the post-medieval period.
The field system is defined by rubble walls, up to 2.5m wide and 0.3m high but
mostly slighter. Where some walls run along the slope they appear as stepped
banks, called lynchets, in the slope profile caused by soil movement on the
gradient against the banks' uphill sides and away from their downhill sides, a
process accelerated by early cultivation. In the east of the monument,
prehistoric walls join and are continued by later drystone walls of three
relatively recent but abandoned field plots, some of whose boundaries overlie
and reuse the prehistoric wall courses.
The field system's pattern in the eastern half of the monument differs from
that in the west. In the east, a major wall extends ESE-WNW along the spine of
the promontory, turning north beside the Heathy Hill Carns to descend the
northern slope as a marked lynchet, 0.75m high, ending at the hut circle
settlement described below. The northern slope contained within the western
part of this wall is occupied by a rounded enclosure close to the east of the
settlement and overlain by a recent wall from post-medieval reuse. Along the
spinal wall, other walls branch off at near right-angles to each side at
irregular intervals, 8m to 60m apart; most run downslope towards the present
coasts but some terminate on bedrock outcrops; another, south of the spine,
curves west to intersect two other walls to give two tiny plots on the upper
slope.
As the spinal wall bends to the north, a wall branches to the WSW and enters
the different field system layout in the west. Here the pattern divides into
transverse segments a strip of land which runs between northern and southern
coastal outcrops which fringe much of promontory's western half. This strip is
subdivided by at least six roughly north west - south east walls, 12m-30m
apart. The walls are near-parallel though some curve slightly and most
terminate at one or both ends on large coastal bedrock outcrops. The eastern
three walls are also crossed by other lengths of walling at various angles but
of similar character, considered to derive from a different phase of land
division. At the western tip of the promontory are remains showing another
dominant axis of field layout: two short lengths of prehistoric wall, 40m
apart, run north east - south west to the southern coastal edge, the
westernmost terminating at a small outcrop at its north east end.
The prehistoric settlement at the northern end of the spinal wall contains two
hut circles, centred 7.5m apart on an east-west axis on the steep slope
descending from the eastern side of the Heathy Hill Carns granite outcrops.
Each is built by levelling the interior partly into the north east facing
slope, the resulting backscarp lined with facing slabs to form the rear wall.
The earth dug out was used to create a slight terrace supporting the forward
edge of the interior defined by a low bank, lowering to give an ill-defined
entrance gap facing north east. The western hut circle has an internal
diameter of 3.5m, with a backscarp up to 0.7m high; the eastern hut circle,
slightly lower on the slope, has an internal diameter of 5m and a backscarp to
1m high, faced with relatively large slabs, up to 0.8m high and 1m long on the
south west side.
In addition to the visible remains of the field system and settlement, a
number of prehistoric flint artefacts have been recovered from various parts
of this monument.
Close to the present north coast of the promontory, 25m NNW of the hut circle
settlement, is a small stone-lined pit, called a kelp pit, visible as an ovoid
hollow measuring 1.6m east-west by 1.1m north-south and 0.5m deep, cut into a
fairly steep northerly slope behind the coastal edge. The original sides and
floor of the hollow are blanketed by deposits of blown sand and leafmould, up
to 0.2m deep; beneath those later deposits, slabs of the pit's stone lining
are detectable on the floor and all sides except the north. Kelp pits are the
sites where seaweed was burnt to produce soda ash in a local industry
practised between AD 1684 and 1835, supplying a vital commodity for the
mainland glass, soap and alum industries.
Beyond this monument, further remains of this prehistoric field system survive
to the north east in the adjacent inter-tidal zone of Great Porth, separated
from this scheduling by the coastal cliff and adjacent erosion. On the higher
lands of Samson Hill and Gweal Hill, from 300m to the east and 450m to the
north west respectively, further survivals of prehistoric field system give
way to cairn cemeteries about their summit areas. In the southern end of Great
Porth are remains of a long-abandoned small quay, 17m north east of this
monument; although such quays occur in several sheltered small bays on Scilly,
they are regularly associated with the sites of kelp pits, facilitating the
off-loading of collected seaweed from small boats. The prehistoric field
systems, cairn cemeteries and the quay are the subjects of separate
schedulings.
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.
