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Prehistoric settlement and field system at Porth Killier, St Agnes

A Scheduled Monument in St. Agnes, Isles of Scilly

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Latitude: 49.8957 / 49°53'44"N

Longitude: -6.3426 / 6°20'33"W

OS Eastings: 88245.062972

OS Northings: 8541.932833

OS Grid: SV882085

Mapcode National: GBR BXQY.X6G

Mapcode Global: VGYC4.0WSB

Entry Name: Prehistoric settlement and field system at Porth Killier, St Agnes

Scheduled Date: 4 October 1996

Source: Historic England

Source ID: 1014998

English Heritage Legacy ID: 15450

County: Isles of Scilly

Civil Parish: St. Agnes

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 hut circle settlement on the south east of
Porth Killier on northern St Agnes in the Isles of Scilly. Extending east from
the settlement, behind Kallimay Point, the monument also includes a broadly
contemporary prehistoric field system.
The prehistoric settlement contains at least three stone hut circles, spaced
1m-2m apart and exposed in an ENE-WSW row along the low coastal cliff face of
south eastern Porth Killier. The hut circles have rounded internal areas, up
to 5m across at their line of truncation by the cliff face and defined by
inner facing walls of granite slabs, largely coursed but incorporating some
edge-set slabs, surviving up to four courses and 0.9m high. The facing in the
central hut circle includes a reused hollowed slab from an early type of
millstone called a saddle quern. The facing walls are backed by layered soil
deposits and middens of occupation debris. Detailed recording of the central
hut circle revealed a floor partly built up of redeposited subsoil and crossed
by a slab-lined and covered drain. Over the floor lay a deep midden deposit
containing a rich assemblage of occupation debris including sherds of Bronze
Age pottery, broken and burnt saddle quern rubber-stones, charcoal, fragments
of limpet shells, fish, bird and sheep or goat bones and charred cereal
The cliff section also reveals that the hut circles are accompanied by
deposits, generally totalling 1m thick, comprising dumped material
contemporary with the settlement and later gradual accumulations. Such
deposits have been recorded at various times over at least 50m of the cliff
face, their south western limit being unknown due to masking by early coastal
defence works. Towards their north east end these deposits include rubble
spreads considered to denote former locations of further hut circle sites; a
saddle quern is known to have eroded from one of these sites onto the upper
In the immediate vicinity of the hut circle settlement, at least eight further
middens have been recorded among the adjacent dumped deposits. Most comprise
small accumulations of limpet shells and bone but the largest extends over
4.5m long and 0.6m deep beside the facing wall of the north east hut circle.
These middens have also produced Bronze Age pottery sherds, both decorated and
plain, and environmental analysis of the midden deposits has revealed bones of
ox, sheep/goat, deer, pig, whale and grey seal, a range of bird and fish
species and the visually dominant limpets. Charred and mineralised plant
remains include wheat and barley, celtic bean and various weeds typical of
arable land. Radiocarbon dating of charred grain from the largest midden gave
a overall date range of 1680-1310 BC, in the Middle Bronze Age, while charcoal
from middens to the north east of the hut circles gave a Late Bronze Age range
of 1375-995 BC. Plant remains from the middens also included indicators of the
wider environmental context contemporary with the settlement.
Behind the cliff face, the inland extent of stratified settlement remains has
been gauged by archaeological prospecting techniques, indicating that the
settlement occupies a large bedrock depression, with sufficient depth of soil
consistent with surviving stratified deposits mapped up to 20m behind the
cliff edge of the settlement.
Besides the Bronze Age settlement remains, prehistoric flint artefacts
indicating earlier settlement have been found eroding from an early soil layer
exposed along much of the south east cliff of Porth Killier up to Kallimay
Point. Finds later than the Bronze Age settlement have also been recovered
from the Porth's eroding cliff, notably sherds of Iron Age pottery, a Roman
copper-alloy brooch and an early medieval sherd. Few such later period finds
were found during recording of the Bronze Age settlement, suggesting a
different focus for the later settlement activity.
The prehistoric field system extends east from the area of the Bronze Age
settlement exposed in the cliff face. On the broad spur behind Kallimay Point,
and where not masked by soil deposits and vegetation, its walling is visible
as lines of variously spaced or contiguous boulders, generally 1.5m wide and
0.5m high. Three walls subdivide the broad spur on a NNW-SSE axis; the central
wall extends along part of the spine of the spur from a small granite outcrop
on its southern summit; the north east wall follows the contour close to the
present coast, turning to and truncated by the coastal cliff at the north. The
third wall, on the spur's western slope, is of different character, surviving
as a pronounced bank, called a lynchet, generally 2m wide and up to 1.5m high,
reflecting movement of soil against the boundary due to the effects of early
cultivation on the slope. At the north its straight course changes to form a
wide curve, truncated on the west by the coastal cliff. A hollow along the
east side of its straight sector is considered to derive from a early
trackway. South west of the lynchet, a fourth boulder wall extends 50m north
east-south west, curving inland at each end where it is truncated by modern
pasture clearance. Further traces of the field system are also apparent in the
unusually sinuous courses of some present field boundaries in the modern
enclosed land immediately south of those on the spur; these sinuous lengths
contrast markedly with the straight-line boundaries laid out in recent
centuries and denote the earlier boundary continuing beneath and influencing
the course of the modern boundary. These preserved lengths include a wall
rising north west-south east to a slight hillock behind the coastally-exposed
settlement focus. There it meets another sinuous wall running north east to
end on one of two roughly parallel boundaries extending north west-south east
along the slope behind Porth Conger; beyond this scheduling, their alignment
is continued in another surviving area of early field system north of Higher
Beyond this monument, further prehistoric field system and settlement sites
survive from 50m to the south east on the land north of Higher Town. These are
the subject of a separate scheduling.
All modern sea defence structures are excluded from the scheduling but the
ground beneath them is included.

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.
Stone hut circles are what remain of the round houses of early inhabitants on
the Isles of Scilly. Excavation has shown that round houses were built on the
islands from the Bronze Age to the early medieval period (c.2000 BC-AD 1066),
though during the Romano-British period (AD 43-400) complex forms were
developed with multiple rooms and annexes, classified separately as `courtyard
houses'. Stone hut circles survive with rubble or earth and rubble walls or
banks defining circular or ovoid internal areas. These are usually levelled
and range from 2.5-13m across, though they are generally 3-5m across. The
walls may incorporate natural ground-fast boulders or outcrops and sometimes
have a facing of edge-set slabs, large blocks or occasionally of coursed
rubble walling along one or both faces. Some hut circle walls show entrance
gaps, 0.5-2m wide, sometimes flanked by end-set slabs or blocks. Remains of
roofing are not preserved but excavations have revealed post- and stake-holes
for roof supports and internal subdivisions. Excavation has also revealed a
range of domestic artefacts and, in a small number of later examples, evidence
for metal working. The deposits within and around hut circles may also include
quantities of midden material. Stone hut circles may occur singly or in small
or large groups, either closely spaced or dispersed. At least 136 hut circles
are recorded on the Isles of Scilly. These are widely distributed but are more
likely to be found towards the lower land, the coastal margins and the inter-
tidal zone, reflecting the subsequent submergence of much low-lying land that
formed the original landscape context in which many such settlements were
built. Hut circles may be associated with broadly contemporary field systems
and funerary monuments, while some examples dating to the Romano-British and
early medieval period are included within sites forming religious foci. They
embody a major part of our evidence on the economy and lifestyle of the
islands' past inhabitants. Their longevity of use and their relationships both
with other monument types and with the islands' rising sea level provides
valuable information on the developing settlement patterns, social
organisation and farming practices throughout a considerable proportion of the
islands' human occupation.

This prehistoric settlement site at Porth Killier contains an unusually good
survival of Bronze Age structural remains in direct association with extensive
and undisturbed contemporary occupation layers. From a programme of detailed
recording, sampling and analysis, this settlement is known to be a
particularly rich and closely datable source of economic, environmental and
artefactual information of national significance for studies of this period;
its faunal assemblage also includes many species not previously recorded in
Bronze Age deposits on Scilly and it forms one of the main sites quoted in
palaeo-environmental assessments of the Isles of Scilly. Despite encroachment
of the coastal cliff, archaeological prospecting has indicated the
considerable area behind the cliff face in which these buried stratified
deposits will survive and has thereby confirmed the long term presence of
important prehistoric settlement remains at this location. The prehistoric
field system in this monument shows clearly the manner of prehistoric land
division employed, and its proximity to similar remains beyond the monument
near Higher Town demonstrate the broader context in which the settlement focus
developed. The lynchetting associated with parts of the field system will also
preserve important information on the development of prehistoric land use,
complementing the data from the settlement.

Source: Historic England


Books and journals
Ashbee, P, Ancient Scilly, (1974)
Ratcliffe, J, Fieldwork in Scilly July 1993, (1994)
Ratcliffe, J, Fieldwork in Scilly 1991 and 1992, (1993)
Ratcliffe, J, Sharpe, A CAU, Fieldwork in Scilly Autumn 1990, (1991)
Ratcliffe, J, Parkes, C, Fieldwork in Scilly: March 1989, (1989)
Ratcliffe, J, Fieldwork in Scilly 1991 and 1992, (1993)
Ratcliffe, J, Lighting up the Past in Scilly, (1991)
Russell, V, Isles of Scilly Survey, (1980)
Gray, A, 'Cornish Archaeology' in Prehistoric Habitation Sites on the Isles of Scilly, , Vol. 11, (1972), 19-49
Ratcliffe, J & Parkes, C/CAU, Fieldwork in Scilly: September 1989, (1990)
Ratcliffe, J & Straker, V, Land Use and Environmental Change in the Isles of Scilly, 1995, Unpubl draft, July 1995, pp 58-62
Ratcliffe, J & Straker, V, Land Use and Environmental Change in the Isles of Scilly, 1995, Unpubl draft, July 1995, pp 58-62
Title: 1:2500 Ordnance Survey Map; SV 8808
Source Date: 1980

Waters, A & Ratcliffe, J/CAU, AM 107 for Scilly SMR entry PRN 7028, (1988)
Waters, A & Ratcliffe, J/CAU, AM 107 for Scilly SMR entry PRN 7029, (1988)
Waters, A & Ratcliffe, J/CAU, AM 107 for Scilly SMR entry PRN 7033, (1988)
Waters, A & Ratcliffe, J/CAU, AM 107 for Scilly SMR entry PRN 7034, (1988)
Waters, A & Ratcliffe, J/CAU, AM 107s for Scilly SMR entries PRN 7028 & 7033, (1988)

Source: Historic England

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