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Mid-16th century blockhouse and ramparts with adjacent walling and occupation deposits at Block House Point

List Entry Summary

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 Culture, Media and Sport.

Name: Mid-16th century blockhouse and ramparts with adjacent walling and occupation deposits at Block House Point

List entry Number: 1013662

Location

The monument may lie within the boundary of more than one authority.

County:

District: Isles of Scilly

District Type: Unitary Authority

Parish: Tresco

National Park: Not applicable to this List entry.

Grade: Not applicable to this List entry.

Date first scheduled: 09-Oct-1981

Date of most recent amendment: 16-Jan-1996

Legacy System Information

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

Legacy System: RSM

UID: 15406

Asset Groupings

This list entry does not comprise part of an Asset Grouping. Asset Groupings are not part of the official record but are added later for information.

List entry Description

Summary of Monument

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.

Blockhouses are small, strongly-built defensive structures, built from the late 14th to mid 17th centuries and designed to house guns and protect the gunners and ammunition from attack, often while being located in a forward or exposed position. Blockhouses vary considerably in form, construction and ground plan but were typically sited as forward defences to cover anchorages, harbours, other defences and their approaches. They include a single free- standing structure, usually built of stone, incorporating a gun platform. The gun platform may be situated in a tower or a bastion. Accommodation for the gunners or look-out troops was of limited extent if provided at all. Of the 27 blockhouses with extant remains recorded nationally, three are located on the Isles of Scilly, each of a different design, built during separate periods and for differing purposes, demonstrating well the diversity of this class of defensive monument.

The blockhouse at Block House Point has survived well, with relatively minor damage from the lowering of the parapet wall. The blockhouse is unusual in including a succession of earthwork defences that complement the masonry structure. The deep deposits of blown-sand that cover much of the eastern side of the headland will preserve broadly contemporary occupation deposits and the blockhouse's seaward defences, confirmed by the walling and land surfaces evident in the dune face. As an integral part of the first post-medieval phase of fortification on Scilly, this monument reflects the rise of national strategic considerations in planning the islands' defences, as evidenced by a range of surviving historical sources giving the context in which this monument was built. The provision of improved living quarters and the mid-18th century indication that the monument was still considered a serviceable fortification, show an unusual longevity, well beyond that of the other defences with which it was erected.

History

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

Details

The monument includes a mid-16th century blockhouse built on a low headland at the south east edge of Old Grimsby Harbour, on the east coast of Tresco in the Isles of Scilly. The blockhouse was defended from landward attack by a single close rampart around the western and southern crest of the headland's summit. Two outer lines of defensive rampart occur on the lower slopes, bringing much of the headland into the defended area. Coastal erosion along the headland east of the blockhouse has revealed mortared walling and occupation deposits within deep deposits of blown sand. The blockhouse is a Listed Building Grade II and, together with the inner rampart, is a monument in the care of the Secretary of State. The blockhouse was built between 1548 and 1552 and survives as a raised gun platform with adjoining living quarters built of randomly coursed granite walling with more regular quoins. The walls rise from the weathered, irregular granite stacks of the underlying outcrops crowning the hill. From there, the blockhouse commands a field of fire to the north west across the entrance of Old Grimsby Harbour and to the north east across the waters between Tresco and Tean, one of several routes of entry to the Scilly archipelago. The gun platform has four unequal sides, tapering from 7.5m long internally on the north west to 5.75m long on the south east, and 6.7m long on the south west to 5.2m long on the north east. The platform level is 2.1m high on the south west, but ends on the north east against a precipitous drop along the outcrop's scarp. The platform has a neatly-paved hard-standing, 2m wide, for artillery along its north west and north east sides. Remains of more irregular granite paving also survive near the south east wall. The platform is defined by a parapet, 1m thick, now partly demolished to 0.5m high or less over the north west, north east and adjoining part of the south east sides. In the wall-section at each end of the reduced parapet, in the north west and south east walls, facing slabs survive from former openings, called embrasures, splayed to both sides to enable guns to fire through the parapet. On the south west, the wall survives to 2.5m high above the platform, with an entrance towards the western corner. The entrance, 1.4m wide and 1.8m high, has a very shallow arch formed from a single lintel slab and is reached by a step down from the platform; outside the entrance, seven steps descend to ground level. A small chamber, 0.9m wide and 0.6m high and now blocked, is located in the inner face of the platform's south west wall immediately south east of the entrance. High up in the same wall, near the southern corner, is a blocked narrow window which lit the blockhouse's original living quarters in this corner; these quarters had a lean-to roof sloping down to the north east, its former line visible in the outer masonry of the south east wall. In the surviving full-height portion of the platform's south east wall, a small storage chamber is built against and partly into the inner face, near the southern corner. This chamber, considered to have housed ammunition or gunpowder, is 1m wide, 0.75m deep and 1.6m high internally, with single-slab jambs and threshold, rebated for a door, and a projecting bevelled lintel. Above the chamber and the adjoining portion of this wall, the masonry is capped by a double layer of bevelled coping slabs. Between the storage chamber and the platform's southern corner, a slab-framed doorway, also rebated for a wooden door, opens onto a stairwell that turns south west, lit by a window in its south east wall, and descends to the later living quarters. These include a single room built against the blockhouse's original south west wall, with a lean-to roof sloping down to the south west. The room measures 3.5m north west - south east by 2.6m north east - south west internally and is lit by a small window in each of the south west and north west walls, plus that in the stairwell. A slab-built fireplace is provided in the south west wall against the southern corner, with a chimney rising from that corner. The inner faces of the walls bear abundant traces of their former plaster. Beyond the blockhouse, the hill slopes gently except to the north east where the steep coastal slope is crowned by the outcrops underlying the blockhouse. The approach to the blockhouse across the gentle slope is defended by a single semicircular rampart around the crown of the hill, ending at the outcrops to the north east. The rampart is visible as an earthen bank up to 10m wide, rising 0.35m high on the inner side and 2m high on the outer. The inner edge of the bank runs 7m-8m beyond the outer walls of the blockhouse, with a slightly in-turned entrance, 2m wide, in the south west, directly opposite the blockhouse's entrance steps. Two further, slighter, ramparts, each 12m-15m wide and approximately 20m apart, survive on the hill's lower slopes, visible on the west and south west but extensively masked by deep layers of blown sand that blanket the southern and eastern sides of the headland. The innermost rampart, to 0.2m high and chiefly visible on the western slope, runs along the contour 40m-45m beyond the blockhouse. The outer rampart, up to 1m high, adopts a north west - south east course near the foot of the south west slope, running towards the saddle that defines the base of the headland. In addition to the surviving remains, our knowledge of this monument is amplified by surviving historical documentation. This blockhouse formed part of a series of fortifications built on Tresco and St Mary's in 1548-1554 during the reigns of Edward VI and Mary in response to threats from the French. An account dated May 1554 described this monument as a blockhouse in the `fissher town', referring to Old Grimsby, and it was accompanied on Tresco in this phase of fortification by a second blockhouse and an artillery castle on the opposite side of the island, 1.6km to the north west, covering the passage between Tresco and Bryher. These fortifications again receive mention in State Papers of 1579. In 1651, the initial attack from Parliamentary forces on the incumbent Royalist garrison on Scilly was made on the adjacent stretch of Tresco's north eastern coastline; this blockhouse is considered to have played a part in mounting the heavy gunfire which the attackers are recorded to have faced before they captured the island. In the following year, the blockhouse is termed `Dover Fort' in the Parliamentary Survey of the islands. In 1750, Heath commented that the blockhouse commanded Old Grimsby harbour `when fitted up', suggesting the structure was serviceable but unarmed. The blockhouse is also recorded by the 18th century antiquaries Borlase and Troutbeck in 1756 and 1796 respectively. Along the north east coast of the headland, from 35m ENE of the blockhouse, erosion of the deep blown-sand deposits has exposed lengths and sections of walling and adjacent old land surfaces within the dune face. These exposures indicate two successive parallel mortared walls, 2m apart, following a north west - south east course, parallel to the present coastline. Although not closely dated, their mortared construction and their implied length has been considered to indicate an origin as lines of seaward defence for the blockhouse. The earlier, north eastern, wall is visible in two exposures, 90m apart, and survives as a stone-faced wall, at least 0.8m wide and 1.3m high, with a core of smaller rubble, all secured by a mortar derived from the local subsoil, called `ram'. The base of this wall is c.2m below the top of the present dunes and cuts through a dark band within the dune that derives from a former land surface when the dune had a period of stability, forming a turf layer. Beneath this land surface, two earlier land surfaces are visible as dark bands in the dune face. The other, later, wall is visible in a single exposure showing only its core rubble, 0.6m high, also set in ram mortar. This wall's base is c.1.6m below the present dune surface and was built on the old land surface that is cut by the other wall. The top of this wall is sealed by another, later and very dark old land surface layer. The old land surfaces both above and below the later wall contain waste from adjacent occupation, evident from numerous limpet shells together with a fragment of glazed pottery previously recovered from the layer immediately beneath that wall, indicating a medieval or later date. A slate fragment has also been found beside the earlier wall section. All English Heritage notices, fixtures, fittings and modern floor surfaces, the wooden seat and the post-and-wire fencing are excluded from the scheduling but the ground beneath them is included.

MAP EXTRACT The site of the monument is shown on the attached map extract.

Selected Sources

Books and journals
Ashbee, P, Ancient Scilly, (1974)
Ashbee, P, Ancient Scilly, (1974)
Borlase, W, Observations on Ancient and Present State of the Isles of Scilly, (1756)
Bowley, R L, The Fortunate Islands: A History of the Isles of Scilly, (1968)
Bowley, R L, The Fortunate Islands: A History of the Isles of Scilly, (1968)
Bowley, R L, The Fortunate Islands: A History of the Isles of Scilly, (1968)
Heath, R, A Natural and Historical Account of the Isles of Scilly, (1750)
Morgan, K O, Oxford Illustrated History of Britain, (1986)
O'Neil, BH St J, Ancient Monuments of the Isles of Scilly, (1949)
O'Neil, BH St J, Ancient Monuments of the Isles of Scilly, (1949)
Ratcliffe, J, Fieldwork in Scilly 1991 and 1992, (1993)
Ratcliffe, J, Fieldwork in Scilly 1991 and 1992, (1993)
Ratcliffe, J, Fieldwork in Scilly 1991 and 1992, (1993)
Ratcliffe, J, Fieldwork in Scilly 1991 and 1992, (1993)
Ratcliffe, J, Scilly's Archaeological Heritage, (1992)
Ratcliffe, J, Scilly's Archaeological Heritage, (1992)
Ratcliffe, J, The Archaeology of Scilly, (1989)
Saunders, A D, 'Cornish Archaeology' in Harry's Walls, St Mary's Scilly; a new interpretation, (1962), 85-91
Saunders, A D, 'Cornish Archaeology' in Harry's Walls, St Mary's Scilly; a new interpretation, (1962), 85-91
Other
Ancient Monuments Terrier & Deed Plan for SI 356, Old Blockhouse, (1984)
Ancient Monuments Terrier & Deed Plan for SI 356, Old Blockhouse, (1984)
consulted 1993, Parkes, C, AM 107 for Scilly SMR entry PRN 7375.01, (1988)
consulted 1993, Parkes, C, AM 107 for Scilly SMR entry PRN 7375.02, (1988)
consulted 1993, Parkes, C/CAU, AM 107 for Scilly SMR entry PRN 7364.01, (1988)
consulted 1993, Parkes, C/CAU, AM 107 for Scilly SMR entry PRN 7364.01-.02, (1988)
consulted 1993, Parkes, C/CAU, AM 107 for Scilly SMR entry PRN 7364.02, (1988)
consulted 1993, Parkes, C/CAU, AM 107 for Scilly SMR entry PRN 7365.02, (1988)
consulted 1993, Parkes, C/CAU, AM 107 for Scilly SMR entry PRN 7375.01, (1988)
consulted 1993, Parkes, C/CAU, AM 107 for Scilly SMR entry PRN 7375.02, (1988)
consulted 1993, Parkes, C/CAU, AM 107s for Scilly SMR entries PRN 7364.01 & 7365.02, (1988)
consulted 1993, Parkes, C/CAU, AM 107s for Scilly SMR entries PRN 7364.01-2; 7365.02; 7375.01-2, (1988)
p 73; Tresco The Blockhouse 0/1/119, DNH, DNH List of Buildings of Special Architectural/Historic Interest, (1992)
Title: 1:10000 Ordnance Survey Maps: SV 81 NE & SV 91 NW Source Date: 1980 Author: Publisher: Surveyor:
Title: 1:2500 Ordnance Survey Map, SV 8715 Source Date: 1980 Author: Publisher: Surveyor:

National Grid Reference: SV 89721 15456

Map

Map
© Crown Copyright and database right 2017. All rights reserved. Ordnance Survey Licence number 100024900.
© British Crown and SeaZone Solutions Limited 2017. All rights reserved. Licence number 102006.006.
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End of official listing