Prehistoric regular field system and hut circle on Great Ganilly


Heritage Category:
Scheduled Monument
List Entry Number:
Date first listed:


Ordnance survey map of Prehistoric regular field system and hut circle on Great Ganilly
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The building or site itself may lie within the boundary of more than one authority.

Isles of Scilly (Unitary Authority)
St. Martin's
National Grid Reference:
SV 94711 14424

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.

This regular field system and the incorporated hut circle on Great Ganilly have survived well, clearly displaying the character of the prehistoric settlement layout and the influence of the topography upon it despite some truncation by rising sea levels. The relationship of the monument's settlement features with the broadly contemporary funerary cairns on the summit of the north west hill demonstrates the wider organisation of prehistoric land use.


The monument includes a prehistoric regular field system extending across the central part of Great Ganilly, the largest of the uninhabited Eastern Isles, south east of St Martin's in the Isles of Scilly. The field system incorporates a small hut circle near the centre of its surviving extent. The prehistoric field system is visible up to about the 25m contour level on the SSW-facing flanks of the island's north west hill, east of Holmbush Carn, and extends across the island's low central saddle to the base of an interglacial wave-cut bench along the foot of the northern flank of the island's south east hill. The field system is defined by turf-covered rubble banks, generally 2m-3m wide and 0.3m high and frequently supporting a line of spaced blocks and edge-set slabs averaging 0.5m high but up to 0.8m high. Where they follow the contour the banks are substantially enlarged, often over 4m wide and 1.5m high, by a process called lynchetting, the accumulation of soil which has been disturbed and brought down the slope by prehistoric cultivation. The area of the field system is divided by near-parallel rubble banks running north east-south west, almost directly downslope and 15m-50m apart on the island's north west hill but with larger intervals, up to 90m wide, evident among the banks across the saddle and on the south east hill where recent wind-blown sand deposits may also mask some finer detail. Most of these walls run directly to the coastal cliff or beach shingle at their seaward ends, denoting their truncation by the rising sea level since they were built. Between these parallel walls, the field plots are defined by further banks along the contour, c.40-50m apart, mostly lynchetted and joining the downslope walls at or near right angles. The field system contains at least one small hut circle, near the south east tip of the north west hill. It is in a sheltered location, protected both by a natural hollow in the hillside north of West Porth and by its position on an artificial terrace in the slope, defined by the field system's lynchetted upper bank 2m north of the hut circle and by a parallel scarp immediately to its south. The hut circle is ovoid, its levelled interior measuring 3.1m east-west by 2.2m north-south, defined by a rubble wall up to 0.7m wide and 0.6m high, but merging with the terrace scarp on the south. Traces of inner facing slabs are visible and an entrance gap 0.5m wide at the east end, flanked on its south by an edge-set slab across the wall line. Some rubble in the interior and entrance is considered to derive from later disturbance. This field system is heavily influenced by the island's topography; the orientation of its hills' slopes determines the dominant axis of the downslope boundaries but effects are also evident at a more detailed level. The upper bank of the field system on the north west hill consistently stops short of the spine along the hill's south east spur, zig-zagging in its course to do so and to avoid rock outcrops, but terminates at an outcrop and natural scarp at its south east end. Other prominent outcrops also form focal points for some field boundaries, including a north east-south west boundary immediately north of West Porth. The field system does not encroach onto the summit area of the island's north west hill, which supports two broadly contemporary funerary cairns.

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.


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

Legacy System number:
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Books and journals
Ashbee, P, Ancient Scilly, (1974)
consulted 1993, Ratcliffe, J/CAU, AM 107 for Scilly SMR entry PRN 7211.02, (1988)
Ratcliffe, J/CAU, AM 107 for Scilly SMR entry PRN 7211.01, (1988)
Title: 1:10000 Ordnance Survey Map; SV 91 SW Source Date: 1980 Author: Publisher: Surveyor:


This monument is scheduled under the Ancient Monuments and Archaeological Areas Act 1979 as amended as it appears to the Secretary of State to be of national importance. This entry is a copy, the original is held by the Department for Digital, Culture, Media and Sport.

End of official listing

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