Samson Flats Inter-tidal Field Survey



The ‘Hedges and Ruins’ on Samson Flats in the Isles of Scilly were first noted by Dr William Borlase in the mid-eighteenth century. The location of these features within the inter-tidal zone was taken as evidence that they were part of an inundated landscape and possibly Broze Age in date (4500 BP – 2700 BP). However, this interpretation of their function and date has sometimes been questioned.

Above: the location of Samson within the Isles of Scily archipelago.

Left: the location of stone built structures (in red) on Samson.


This project has been commisioned by English Heritage and aims to produce an accurate survey of the features and topography in the inter-tidal zone on Samson Flats. The survey of these features should allow a better determination of their function and antiquity. The project will also seek to engage the local community through site open days and local presentations.

The principal archaeological features visible on Samson Flats are linear stone features set into the sand of the inter-tidal zone. Several interpretations of these features have been voiced. These features could be associated with prehistoric settlements, fish-trapping or the kelp burning industry


An aerial photo of Samson Flats. Although the photograph was taken at high tide the network of archaeological features close to the shoreline is still plainly visible.


Submerged Prehistoric Settlement

There are seven HER records for Samson Flats. Of these, two are classified as ‘Field Systems’ and four as ‘Hut Circles’. Thomas suggests that the linear structures on Samson Flats might form part of a field system that extends over much of the island. It has been suggested that these features are Bronze Age in date and present models for sea level rise in Scilly suggest that such a date is feasible.

Sea level rise in Scilly from 9000 years Before Present (BP) to present day.

After Rapid Coastal Zone Assessment for the Isles of Scilly. HES, Truro 2004

Fish Traps

Although Crawford originally wrote in support of the submerged field boundary hypothesis he later suggests, in an editorial for Antiquity , that these features might instead be the remains of medieval fish traps . Bannerman and Jones state that seven types of fish trap can be identified, although variations upon these can be demonstrated. All types work on the same principle, acting to either isolate fish within a broad area or guide them towards a staked net during the ebbing tide.




Natural feature adapted as a trap


Semi-permanent wattle and wood trap


Modified natural feature trap


Crescent – shaped trap


Rectilinear trap


The V or Double V – shaped trap


The S – shaped weir trap

Fish-trap types, after Bannerman and Jones

The dating of stone built fish-traps is often problematic. However, timber stakes found in association with stone built traps at Strangford Lough, Co. Down, have been dated to the late medieval period . Historical sources have also been used to date a trap in Caernarfon, North Wales, to the 12th or 13th century and fish-traps in Scotland are known to have been used well into the 19th century .

Ashbee and Hooley state that the alignment, position and construction of the linear features on Samson Flats all indicate they would function poorly as fish traps. High resolution survey of the features and surrounding topography should help resolve these issues.


Kelp Industry

The collection and burning of kelp for the extraction of sodium carbonate and iodine formed a seasonal industry in Scilly from the mid 17th to 19th century. There are three types of archaeological feature associated with the kelp industry which are analogous with the inter-tidal remains on Samson Flats: drying walls, territorial boundaries and structures designed to encourage kelp growth.

‘Field walls’ in the inter-tidal zone on Samson Flats


Above & Right: ‘Field walls’ in the inter-tidal zone on Samson Flats.


Inter-tidal structures intended to increase yield – these are evidenced at Strangford Lough in Co. Down, Northern Ireland. They were shallow linear structures built within the inter-tidal zone in order to encourage the growth of kelp.

Drying walls – structures intended to keep kelp off wet ground, thus allowing it to dry thoroughly in advance of burning. These are prevalent features in both Co. Donegal and Rathlin, Northern Ireland .

Territorial boundaries - Johns et al suggests that the linear features on Samson Flats might represent boundaries between kelp territories. Thomas cites historical accounts of disagreements in Scilly regarding kelp collection in certain areas.


Project Aims and Objectives

  • Involvement of the local community and schools in the project by means of guided site open days, school visits and presentations.
  • Involvement of the community in the survey: CISMAS members will undertake the fieldwork and recording. All participants in the fieldwork will be volunteers.
  • Determination as to the most efficient survey methods in the inter-tidal zone, yielding sufficient detail to facilitate the interpretation of function and monitoring the site deterioration processes.
  • Completion of an accurate survey of feature positions and alignments using RTK GPS.
  • Detailed recording of exposed features consisting of 1:20 planning frame drawings and 1:10 profiles.  Such detailed recording may show any inter-relationships between features and lead to a relative dating sequence.
  • Production of a high resolution contour survey of site topography.


Survey Methodology

An RTK GPS system will be used to fix the control point network employed in the survey of the visible features. It will also be used to gather data for the overall contour survey of the area. Once the general position and alignment of the features is established, they will be characterised by drawing representative sections of the features. This will be accomplished by a 1:20 planning frame survey and 1:10 profiles and cross-sections. These will be undertaken in the first year. In the second year further detail will be added, resulting in more of the features being drawn in detail.

An inter-tidal survey being conducted using a Leica Real Time Kinematic (RTK) Global Positioning System (GPS). An inter-tidal survey being conducted using a Leica Real Time Kinetic GPS


The Samson Flats inter-tidal field survey is to be a two year project funded by English Heritage. The first week of field work took place in June 2009, with a further week of survey planned for 2010. For further information see the Interim Report at the Download Centre or Contact Us.


English Heritage


The Samson Flats Inter-tidal field survey is sponsored by:

Opti-cal Survey Equipment Isles of Scilly Travell
Opti-cal Survey Equipment Isles of Scilly Travel