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Civil War battery at Carn Leh, St Mary's

A Scheduled Monument in St. Mary's, Isles of Scilly

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Latitude: 49.9092 / 49°54'33"N

Longitude: -6.301 / 6°18'3"W

OS Eastings: 91317.565833

OS Northings: 9868.236693

OS Grid: SV913098

Mapcode National: GBR BXTX.QN8

Mapcode Global: VGYC4.QJSZ

Entry Name: Civil War battery at Carn Leh, St Mary's

Scheduled Date: 23 September 1994

Source: Historic England

Source ID: 1008330

English Heritage Legacy ID: 15311

County: Isles of Scilly

Civil Parish: St. Mary's

Traditional County: Cornwall

Lieutenancy Area (Ceremonial County): Cornwall

Church of England Parish: Isles of Scilly

Church of England Diocese: Truro


The monument includes a gun battery dating to the English Civil War situated
at Carn Leh, a small rocky peninsula defining the southern edge of Old Town
Bay on St Mary's, in the Isles of Scilly.

The battery extends across the south east sector of the small coastal shelf
bordering the massive granite outcrop named Carn Leh. The battery's internal
area measures 40m long, NW-SE, tapering in width from 20m at its south east
end to 10m wide at its north west end. It is defined to the NNW by Carn Leh
and to its south east by the rocky shoreline. Between those natural features,
its internal area is defined by two earth and rubble banks. The western bank
extends for 20m SSE across the shelf from the Carn Leh outcrop to a small
outcrop beside the foreshore and forms a scarp 0.5m high facing west, gently
dipping to ground level to the east over a width of 2m. The eastern bank
follows the shallow `S-shaped' curve of the slight coastal cliff, extending
for 30m south east from near the eastern face of the Carn Leh outcrop to the
eastern tip of the small peninsula. This eastern bank has lost its outer,
north eastern, side due to coastal erosion of the underlying sea cliff; its
inner slope is now visible up to 0.5m wide and 0.5m high. This bank is
accompanied by a ditch, up to 1m wide and 0.4m deep, along its inner,
south west, side. Within the broader south east end of the battery, adjacent
to the end of the coastal bank and ditch, is the slightly sunken gun pit,
visible as an oval hollow measuring 9m NW-SE by 6m NE-SW and 0.4m deep,
defined along its north east edge by an additional bank, 1.5m wide and 0.5m

The battery at Carn Leh commanded the entrance to Old Town Bay, which contains
one of the principal harbours and settlements on the main populated island of
St Mary's, the military and administrative focus of the Isles of Scilly during
the Civil War. This battery is complemented by another Civil War battery on
the opposite side of the entrance to Old Town Bay, while other contemporary
batteries located on Peninnis Head, south of Carn Leh, extended the field of
fire to the southern approaches to St Mary's Sound.

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.
Civil War fieldworks are earthworks which were raised during military
operations between 1642 and 1651 to provide temporary protection for infantry
or to act as gun emplacements. The earthworks, which may have been reinforced
with revetting or palisades, consist of earth and rubble platforms or banks
and ditches.
The Civil War fieldworks of the Isles of Scilly form a major part of the 150
surviving examples of fieldworks recorded nationally. They present an
unusually complete system of fortifications from this period, both in the
surviving range of fieldwork types represented and in the surviving pattern of
their strategic disposition.
Three main types of Civil War fieldwork have been recognised on the Isles of
Scilly: breastworks, batteries and platforms; these could be deployed
separately or in combination to form a defensive complex.
Breastworks, which on the Isles of Scilly run beside the coastal cliff edge,
consist of an earth and rubble bank, up to 4m wide and nearly 2m high but
generally much smaller, usually accompanied by a ditch on the landward side.
Sixteen surviving examples are recorded on the island.
Batteries are levelled areas or platforms, generally up to 20m across,
situated on a hilltop or terraced into a slope to serve as gun emplacements.
They vary considerably in size and shape and are usually partially or wholly
enclosed by a bank, occasionally incorporating one or two outer ditches.
Twenty batteries survive on the Isles of Scilly, several connected by
breastworks. Adjacent to some batteries are examples of the third fieldwork
type, platforms. These are partly terraced into, and partly out from, sloping
ground and represent sites of lookouts and temporary buildings. Eight such
platforms, measuring up to 12m by 8m in size, are known to survive on the
islands. These fieldworks and fieldwork complexes were occasionally associated
with other classes of defensive monument on the islands, including earthen
artillery forts and blockhouses.
The fieldworks were designed to defend the deep water approaches to the
islands, especially St Mary's where most examples are found. Fieldworks are
also known from Tresco, Bryher, Samson, St Agnes and Gugh. The circumstances
of their construction are recorded in contemporary historical documents which
indicate most were built by the Royalist forces which controlled the islands
for the entire Civil War period except during 1646-8.

This Civil War battery at Carn Leh has survived substantially intact. Although
parts of one outer bank have been lost to coastal erosion, its internal area
remains complete, retaining a good example of a gun pit. Its situation and the
survival of documentation giving the historical context in which this battery
was built demonstrates clearly the strategic methods employed by the Civil War
military forces and the function of batteries within them. This is also
illustrated by the survival of the complementary Civil War batteries, one on
the opposite side of Old Town Bay and the others on Peninnis Head guarding the
approach to St Mary's Sound.

Source: Historic England


consulted 1993, Waters, A., AM 107 relating to Cornwall SMR entry for PRN 7415, (1988)
consulted 1993, Waters, A., AM 107 relating to Cornwall SMR entry for PRN 7555, (1988)
Title: 1:10000 Ordnance Survey Map; SV 90 NW
Source Date: 1980

Title: 1:2500 Ordnance Survey Map; SV 9109
Source Date:

Source: Historic England

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