Iron Age to Romano-British fogou on northern Peninnis Head, 170m south of Carn Gwavel Farm, St Mary's


Heritage Category: Scheduled Monument

List Entry Number: 1020142

Date first listed: 05-Apr-2001


Ordnance survey map of Iron Age to Romano-British fogou on northern Peninnis Head, 170m south of Carn Gwavel Farm, St Mary's
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The building or site itself may lie within the boundary of more than one authority.

District: Isles of Scilly (Unitary Authority)

Parish: St. Mary's

National Grid Reference: SV 90971 10183


Legacy Record - This information may be included in the List Entry Details.

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.

Fogous are walled underground passages constructed during the later Iron Age (about 400 BC to AD 50), though with evidence for their use continuing into the Romano-British period, in at least some cases to the 2nd century AD. The ground plan of fogous varies considerably but all include a drystone-walled passage, the largest being 30m long and 2m wide, roofed by flat cover-slabs and with an entrance at one or both ends. The few excavations of fogous have shown that the walling was initially built and roofed in a trench which was then backfilled. The passage is often curved or `S'-shaped and several surviving examples include subsidiary passages or chambers whose entry from the main passage may be constricted by a narrow creep passage. More than one phase of construction is evident in some cases. Most surviving fogous are located close to or within contemporary settlements, often courtyard house settlements but also including embanked enclosed settlements called rounds. Various suggestions have been offered for the functions of fogous, with particular support for their interpretation as safe refuges during raids, religious sanctuaries or cool storage areas for foodstuffs. At least twelve fogous are known to survive nationally, with five other possible survivals. Their national distribution is restricted to the far west of Cornwall, to Penwith and around the upper Helford River, and with this single example on the Isles of Scilly. The fogou on northern Peninnis Head, 170m south of Carn Gwavel Farm survives very well. Its presence on Scilly provides a significant extension of the distribution of this monument class and is an important addition to the known range of structural features pertaining to the latter part of the Iron Age on the islands. Despite some collapse of the original entrance passage as evident through the creep, and two very minor roof falls in the accessible inner passage, this fogou is one of very few whose built structure and original deposits will remain almost intact and unexcavated. Consequently it is of considerable significance for the study of this enigmatic class of monument and its role in the lives of the later prehistoric and Romano-British communities in the far south west of England.


Legacy Record - This information may be included in the List Entry Details.


The monument includes an Iron Age to Romano-British underground walled passage called a fogou, situated on a north easterly midslope at the northern end of Peninnis Head on St Mary's in the Isles of Scilly. The fogou survives with an underground chamber-like passage measuring 4.97m long, north east-south west, by up to 1.18m wide and 1.18m high. Limited roof collapse near the north east end of passage reveals that the top of its cover- slabs at that point lie 0.4m-0.48m beneath the present ground surface. Its floor remains roughly level but in plan the passage undergoes a shallow `S' curve throughout its length, terminating in the south west at an oblique narrow end-wall, but closed by a broader transverse wall at the north east end. At the foot of the north east end-wall, on its south east side, is a very low narrow opening covered by a large lintel slab. This opening, called a creep, formed the original constricted point of entry into the passage, which comprised the innermost chamber of the fogou. The creep, 0.57m wide by 0.27m high, is visible for up to 1.36m before becoming wholly blocked by collapsed debris. Shortly before that blocking, the creep widens on its north west side and is considered to extend further as the fogou's original entrance from the ground surface. The passage is walled by granite slabs, generally 0.2m to 0.5m across, laid in five to seven rough courses; the base of the wall also includes three relatively small edge-set slabs, to 0.4m high: two adjacent at the south west end and one nearby in the south east wall. The larger spaces between wall slabs are frequently infilled by small pebbles and the local subsoil, called ram, which is considered to have been applied deliberately as a mortar, a practice known from prehistoric stone-built monuments elsewhere on Scilly. At their upper levels, the passage walls curve gently inwards as each course of slabs projects slightly beyond that immediately beneath, a technique known as corbelling. The lower masonry of the passage's south east side-wall continues into the creep without any joint, confirming that the creep and the passage are of one build. The passage is roofed by five large cover-slabs laid flat across the top of the walls and ranging from 0.47m to 0.86m wide. The central cover slab and that to its north east almost touch, but gaps 0.25m-0.37m wide separate the others. The gaps separating the south western and north eastern cover slabs from those adjacent to them are infilled by small boulders and rubble: it was limited collapse of this infill in the north eastern gap in May 2000 that led to the discovery of the fogou and created the present aperture by which the passage has been examined. By contrast, the space between the central cover slab and that to its south west is closed by a row of smaller slabs laid neatly across the gap from above; this is a later modification following a previous and unrecorded collapse of the gap's rubble infill which produced a mound of soil and silt, with loose slabs along its southern edge, on the passage floor directly beneath the gap. Beyond the soil mound and rubble from that previous collapse, the earth floor of the passage combines patches both of subsoil and dark ploughsoil, the result of silts filtered through the roof and wall, and some recent contamination by visitors examining the passage. However, in the absence of evident excavation or other disturbance to that surface, any stratified floor deposits pertaining to original activity within the passage will survive intact beneath the visible surface. Beyond this monument, there is evidence for settlement and ritual activity in the surrounding area both before and after the period of fogou construction. Funerary cairns dating to the Bronze Age survive on high ground at both ends of the broad headland of Peninnis Head, the nearest being situated only 185m north west of this monument, while Middle to Late Bronze Age settlement sites are exposed along the western coastal cliff of Peninnis Head, with prehistoric field systems surviving further south around the flanks of the headland. These form the subject of separate schedulings. Evidence from the Roman period includes stone artefacts found nearby in the Hughtown area during the 19th century, an altar stone and several column fragments, showing the likely presence there of a Romano-Celtic temple.

MAP EXTRACT The site of the monument is shown on the attached map extract. It includes a 5 metre boundary around the archaeological features, considered to be essential for the monument's support and preservation.


The contents of this record have been generated from a legacy data system.

Legacy System number: 15560

Legacy System: RSM


Books and journals
Ashbee, P, Ancient Scilly, (1974)
Clark, E, Cornish Fogous, (1961)
Maclean, R, 'Cornish Archaeology' in The Fogou: an investigation of function, , Vol. 31, (1992), 41-64
Thomas, C, 'CBA Research Report: Roman Settlement in Roman Britain' in The Character and Origins of Roman Dumnonia, , Vol. 7, (1966), 74-98
During site visit on 9/2/2001, Information told to MPPA by Gill Arbery, IoS FMW & Cons Officer, (2001)
During site visit on 9/2/2001, Information told to MPPA by Jonathan May of Peninnis Flower Farm, (2001)
Startin, D W A, Halligey Fogou: Excavations 1980-82, Unpublished first draft
Title: 1:10000 Ordnance Survey Map SV 91 SW & 1:2500 Ordnance Survey Map SV 9010 Source Date: 1980 Author: Publisher: Surveyor:

End of official listing