Prehistoric field system and stone setting, Civil War fieldworks, post medieval kelp pits and quay on Toll's Island, St Mary's


Heritage Category: Scheduled Monument

List Entry Number: 1015660

Date first listed: 07-Oct-1976

Date of most recent amendment: 21-Jan-1999


Ordnance survey map of Prehistoric field system and stone setting, Civil War fieldworks, post medieval kelp pits and quay on Toll's Island, St Mary's
© Crown Copyright and database right 2018. All rights reserved. Ordnance Survey Licence number 100024900.
© British Crown and SeaZone Solutions Limited 2018. All rights reserved. Licence number 102006.006.
Use of this data is subject to Terms and Conditions.

The above map is for quick reference purposes only and may not be to scale. For a copy of the full scale map, please see the attached PDF - 1015660 .pdf

The PDF will be generated from our live systems and may take a few minutes to download depending on how busy our servers are. We apologise for this delay.

This copy shows the entry on 17-Dec-2018 at 04:42:47.


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 93040 11972


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.

The prehistoric, Civil War and post-medieval elements in this scheduling on Toll's Island each survives well. The prehistoric field system displays clearly its pattern and relationship to the topography while the nearby field system on Mount Todden illustrates its wider prehistoric context, giving valuable evidence for the organisation of land use in the pre-submergence landscape of the islands. The stone setting, respected by the field system walls, is a very rare prehistoric ritual structure known from some upland areas on the mainland and unique on Scilly. The situations of the battery and breastworks on Toll's Island and their wider context within the extensive surviving Civil War defensive system on Scilly demonstrates clearly the strategic methods employed by the mid-17th century military forces and the function of these fieldwork types within them. This scheduling also contains the largest surviving group of kelp pits on Scilly and shows well their characteristic form, features and coastal location near the rocky shores productive of the seaweed they consumed. Their association with the abandoned quay and its trackway in this scheduling illustrates the main range of surviving elements of the kelp industry, a major contributor to the islands' economy in the early post-medieval period.


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


The monument includes a prehistoric field system and stone setting, together with adjacent breastworks and a gun battery dating to the English Civil War on Toll's Island, a small island linked at low tide levels to the north east coast of St Mary's in the Isles of Scilly. The monument also includes four post-medieval kelp pits behind the island's southern coast; the kelp pits are associated with a small quay, also included within the monument, near the island's western tip. The field system divides much of the island into subrectangular blocks by fairly straight boundaries, visible as slight rubble walls, up to 1m wide and 0.2m high, mostly masked beneath the turf. The walls incorporate a midline row of edge- or end-set slabs, generally 0.5m-0.6m high and spaced 1m-2m apart. The field system has a spinal wall running approximately 75m ENE-WSW along the island's summit crest and western slope, from the much later Civil War battery on the highest land at the east to a relatively recent enclosure wall on the north western lower slope. On the west of the island's summit crest, the spinal wall is interrupted by the scattered upstanding slabs of a small granite outcrop embellished to give the stone setting described below. From the west of that break a wall runs SSE then turns ESE along the upper southern slope to form the top boundary of a row of rectangular fields defined by at least three further walls running SSW directly down the island's southern flank. On the island's northern flank, the end walls of the recent enclosure occupying the north west slope also run directly downslope and are considered to reuse courses of the prehistoric plot boundaries. The stone setting west of the island's summit, and respected by the break in the field system's spinal wall, is visible as a group of five narrow upstanding slabs, up to 1.3m long, 0.9m high and 0.8m thick, their long axes oriented ENE-WSW and arranged in two lines north and south of a rectangular area 5m long, east-west, by 2.3m wide. At least two slabs appear as natural bedrock protrusions, embellished to produce the artificial setting by the addition of the other edge-set slabs; one of the latter leans inwards at the centre of the north side, while another, on the south east of the setting, shows traces of a slight rubble mound around its base. During the English Civil War, from 1642 to 1651 on Scilly, Toll's Island became a focus of fortification by virtue of its strategic position at the entrance to Crow Sound, a main maritime route into the archipeligo, and because of the sheltered landing place offered by Pelistry Bay in which the island lies. The surviving fieldworks reflect both aspects. A large gun battery, known as Pellew's Redoubt, was built on the island's highest point behind its north east coast, giving a field of fire across Crow Sound and its approach from the east. The battery is kidney-shaped in plan to give two forward flanks, facing east and north west. It survives as a raised platform of earth and rubble, 22m long, north east-south west, by up to 13m wide externally, its outer scarp rising to 1.5m high to a perimeter bank, 4m wide, around a levelled interior whose surface is approximately 1m above the surrounding ground level. Occasional facing slabs are visible on the outer scarp, which dips on the west to give an entrance gap 1.3m wide. Slight quarry hollows are visible beyond the south east and north west of the battery. The battery is complemented by two lengths of breastwork as defences against enemy landings; each is visible as an earth and rubble bank parallel with, and close to, the coastal cliff and backed by a shallow ditch. One breastwork extends for 23m along the western half of the island's south coast; the other runs for 26m behind the north east coast, from near Pellew's Redoubt to a prominent outcrop to the south east. Along the island's lower southern flank is a row of four kelp pits, sites where gathered seaweed was burnt to give soda ash in a local industry lasting from 1684 to 1835, supplying the resulting product to the mainland glass, soap and alum industries. The kelp pits are unevenly spaced over approximately 75m in an ESE-WNW line, from 0.1m to 15m behind the cliff edge. They survive as inverted-cone shaped hollows, ranging from 1.3m to 1.6m in diameter and 0.4m to 0.6m deep, lined by slabs generally 0.3m-0.5m across with one laid flat at the base, but employing distinctly smaller slabs in the eastern kelp pit. Some slabs have reddened and degraded surfaces from their former heating; two pits have a slight raised lip of slabs, to 0.1m high, around their perimeter, and two have a scatter of small slabs up to 2m from their edges, considered to be discarded fragments of old pit linings. To the south of the island's western tip are remains of a small quay in the inter-tidal zone, long-disused but one of several such quays closely associated with sites of kelp pits on Scilly. The quay is up to 3m wide, 1.5m high and 19m long, running south from the dense boulder spread on the middle shore then curving south west and tapering to end at a large boulder with an iron mooring ring set in its top. Another such boulder set with a mooring ring is located in the bay several metres south of the quay's tip. The quay has a boulder core faced by roughly coursed boulder walling. From the upper end of the quay, a broad track runs east onto the upper shore; it is 2.75m-3.5m wide, cleared through the shore rubble and defined by up-ended boulders but it is now partly inundated by boulders subsequently washed in and its course is disrupted by wave action 10m before reaching the present coastal cliff of the island. Near the junction of the track with the quay is another boulder set with an iron ring. The prehistoric field system and Civil War fieldworks in this scheduling complement other contemporary remains on the nearby coast of St Mary's. The field system is inter-visible with another prehistoric field system on Mount Todden, 350m to the south west across Pelistry Bay but formerly linked by dry land in the pre-submergence landscape when these field systems were laid out and used. The Civil War fieldworks on Toll's Island formed an integral part of a defensive system that extended around the coast of St Mary's, including two gun batteries on Mount Todden to the south and two on Toll's Hill to the north west; Toll's Hill also contains two Civil War platforms and a coastal breastwork, from 250m north west of this scheduling.

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: 15474

Legacy System: RSM


Books and journals
Over, L, The Kelp Industry in Scilly, (1987)
Over, L, The Kelp Industry in Scilly, (1987)
Over, L, The Kelp Industry in Scilly, (1987)
Norway, A H, 'The Cornish Magazine' in The heroic actions of Lord Exmouth, , Vol. I, (1898), 375-388
Parkes, C/CAU, AM 107 for Scilly SMR entry PRN 7232, (1988)
Parkes, C/CAU, AM 107 for Scilly SMR entry PRN 7233.01, (1988)
Parkes, C/CAU, AM 107 for Scilly SMR entry PRN 7233.02, (1988)
Parkes, C/CAU, AM 107 for Scilly SMR entry PRN 7233.03, (1988)
Parkes, C/CAU, AM 107 for Scilly SMR entry PRN 7237, (1988)
Parkes, C/CAU, AM 107 for Scilly SMR entry PRN 7238, (1988)
Parkes, C/CAU, AM 107 for Scilly SMR entry PRN 7239, (1988)
Parkes, C/CAU, AM 107 for Scilly SMR entry PRN 7646, (1988)
Rees, S E, AM7 for Scilly County Monument SI 1024, (1975)
Title: 1:10000 Ordnance Survey Map; SV 91 SW Source Date: 1980 Author: Publisher: Surveyor:
Title: 1:2500 Ordnance Survey Map; SV 91 SW Source Date: 1980 Author: Publisher: Surveyor:
Title: 25": 1 mile Ordnance Survey Map; Cornwall sheet LXXXVII Source Date: 1908 Author: Publisher: Surveyor:

End of official listing