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South Walls, Outer Green Hill

Broch (Iron Age)(Possible)

Site Name South Walls, Outer Green Hill

Classification Broch (Iron Age)(Possible)

Alternative Name(s) South Waas

Canmore ID 9448

Site Number ND38NW 9

NGR ND 3425 8958

Datum OSGB36 - NGR


Ordnance Survey licence number 100057073. All rights reserved.
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Administrative Areas

  • Council Orkney Islands
  • Parish Walls And Flotta
  • Former Region Orkney Islands Area
  • Former District Orkney
  • Former County Orkney

Archaeology Notes

ND38NW 9 3425 8958

Outer Green Hill is a turf-covered stony mound; no wall-faces are visible, but size, content and situation suggest a broch.

Resurveyed at 1:2500.

Visited by OS 17 June 1967.

This is a green mound, some 20m in diameter and 2.5m high, beside the lighthouse road on Cantick Head. It is substantial enough to contain a modest broch; some protruding slabs on the outermost fringes of the mound suggest outbuildings, and there is an erosion-exposure of tumbled rubble in the shoreline.

RCAHMS 1946; 1989, visited August 1987.


Publication Account (2002)

ND38 3 OUTER GREEN HILL ('Cantick Head')


Possible broch in Walls and Flotta on Hoy, an 2.44 m (8 ft.) high, turf covered hillock, 20 m in diameter and a few yards from the shore. Stones project from the grass and there is a well nearby.

Sources: 1. OS card ND 38 NW 9: 2. RCAHMS 1946, 2, 339, no. 1006: 3. Lamb 1989, 18.

E W MacKie 2002

Geophysical Survey (30 April 2007 - 4 May 2007)

ND 342 893 As part of an on-going landscape investigation project Orkney College Geophysics Unit was commissioned to undertake an extensive programme of geophysical survey across Cantick peninsula, South Walls, between 30 April–4 May 2007. A total of 5ha of gradiometer and 1.2ha of resistivity was completed over six separate areas across the peninsula, to cover the majority of the upstanding monuments. This included

all differing types of sites to assist in the identification of unclear/ unknown site types, to allow for comparative study between similar sites, and to collect data to allow for a wider landscape interpretation to assist in gaining a better understanding of the archaeological development of the peninsula. The results clearly show the broch and associated settlement of Green Hill of Hestiegeo broch (ND38NW 8), while the settlement to the E is obscured by the presence of an igneous dyke. The Outer Green Hill broch (ND38NW 9) mound is certainly artificial but does not now look like a broch. The anomalies indicate midden and structures but they are rectilinear in form. Cantick Farm burnt mound (ND38NW 4) shows up well as a very high magnetic and high resistance anomaly with potentially associated structural elements surviving around it. The Bronze Age barrow (ND38NW 5) at Roeberry is clearly visible with both techniques, while the three earthen dykes to its W do not show up well in either the gradiometer or the resistivity results. Unfortunately the results of the survey of the potential prehistoric mounds at

Storehouse and the group at the Ruff of Cantick (ND38NW 17; ND38NW 18; ND38NW 19; ND38NW 16) was inconclusive, with Storehouse having a mix of possible prehistoric and modern origins.

Reports to be deposited with the Orkney SMR andRCAHMS.

Funder: Orkney Islands Council

J Robertson 2007

Excavation (30 June 2008 - 12 July 2008)

ND 3426 8957 Evaluation excavations on a large grassy mound, c20m wide and 2.5m high, took place 30 June–12 July 2008. This represents the third phase of research into the Cantick area and continues the work of the late Judith Robertson, who undertook an archaeological landscape survey of the area in 2006 (DES 2006) and targeted geophysical surveys of the main features in 2007 (DES 2007). The mound had been assumed to represent a broch, but the geophysical survey did not indicate features typical of this type of structure. The

results suggested a squared internal setting perhaps more indicative of a Neolithic tomb or Norse stronghold. The 2008 work aimed to establish the date and character of the mound and place it within the multi-period landscape of Cantick.

A wedge-shaped trench (13m long x 1.5–4m wide) extending from the top of the mound down the S slope

revealed the central chamber and outer revetment walls of a Neolithic chambered tomb. The central chamber consists of two parallel internal corbelled wall faces that appear to form the upper part of a chamber oriented E/W. The chamber is c1m wide at the top and widens to 1.4m where excavations stopped at a depth of 0.9m.

The hollow visible in the top of the mound was confirmed as the result of unrecorded antiquarian excavations. The upper part of the chamber was filled with loose stony backfill which contained several pieces of probable Late Neolithic pottery and frequent small mammal bones, including the first identification of the Orkney vole on the island. It is unclear whether the roof was intact prior to the antiquarian excavations, but this seems unlikely from the quantity of backfill and spoil that surrounds the summit of the mound.

The mound surrounding the central chamber consists of a solid wall-like core with an external inward sloping

revetment wall that survives to over 1m in height. The side of the mound consists of loose collapsed and slumped stony deposits which overlay the revetment walls. A second outer revetment wall was located 3m to the S of the main wall and may represent secondary consolidation of an already denuded mound.

A second small trench was opened on the E side of the mound and revealed the continuation of the main outer revetment wall, mound core and the top of a right-angled internal wall setting that is likely to relate to the central chamber and perhaps forms part of an entranceway or internal side cell. Limited excavation was carried out in this area and the position of the entrance was not established.

The chamber walls, mound core and external revetments are constructed from large water-worn beach slabs. Similar beach slabs have been used in the Later Neolithic chambered tomb at Quoyness, Sanday. The corbelled central chamber walls are typical of Maes Howe-type tombs that are generally assigned to the Late Neolithic.

Report: Orkney SMR and RCAHMS (intended)

Funder: Orkney Islands Council

Daniel Lee (ORCA), 2008


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