1. Between 5th-8th April 2017, the Skomer Island Project Team undertook a small excavation (8m x 0.6m) on a deep field lynchet in the southern part of the island in a bid to recover undisturbed deposits and buried soils suitable for multiple analyses. It is hoped that charcoal and luminescence samples (by Aberystwyth University) taken from the lynchet may help to establish absolute chronological markers for key phases in the development of the Island's fields and settlements, while further environmental sampling (by Cardiff University) will allow the more accurate reconstruction the environmental history of the island. Samples were also taken for the micromorphological analysis of soils by the University of Sheffield.

The previous year's (2016 - NPRN 421796) excavated section of a field lynchet in the North Stream settlement was successful in allowing us to characterise the field boundary; however bracken penetration and a lose stone/soil matrix meant that the lower layers of the lynchet were not sufficiently intact and sealed to allow scientific dating, either by radiocarbon or OSL. The results of palaeoenvironmental and macrofossil analysis by Aberystwyth University is awaited at the time of writing.

The 2017 trench, aligned north-south, was excavated to a depth of 1.1m; the lower levels were waterlogged reflecting both a previously wet winter and the proximity of the lynchet to the boggy valley of South Stream. Seven contexts were identified, revealing an instructive sequence illustrating the clearance of initial field stone early in the history of the boundary, followed by successive build ups of cleared stone, plough soil and ? crucially ? layers of hillwash from higher slopes to the north which contributed to the overall depth of deposition in the lynchet.

The team comprising Bob Johnston (University of Sheffield), Oliver Davis (Cardiff Uiversity), Louise Barker and Toby Driver (RCAHMW) was joined by Professor Geoff Duller from Aberystwyth University's luminescence laboratory who undertook sampling under controlled conditions.

T. Driver & L. Barker, RCAHMW, April 2017

2. The small excavation trench on a deep field lynchet near the South Stream Settlement was opened in a bid to recover undisturbed deposits and buried soils suitable for Optically Stimulated Luminescence (OSL) dating to help to establish absolute chronological markers for key phases in the development of the Island’s fields and settlements, and to assist further environmental sampling to more accurately reconstruct the environmental history. The 2017 trench, aligned north-south, measured 6.1m x 0.6m and was excavated to a depth of 1.1m with the lower levels were waterlogged. Seven contexts were identified, revealing an instructive sequence illustrating the clearance of initial field stone early in the history of the boundary, followed by successive build ups of cleared stone and plough soil contributing to the overall depth of deposition in the lynchet.

The results of OSL dating (Duller and Roberts 2019; section 7) were received in June 2019, bringing new precision to our understanding of the development of agriculture and settlement on the island. The technique has produced the first scientifically dated evidence for Middle Bronze Age, Middle Iron Age and Medieval clearance and farming on Skomer Island.

The 2017 evaluation trench provided only the second excavated cross-section of a field lynchet on prehistoric Skomer and thus stands as a useful comparison with the North Stream Settlement lynchet excavated in 2016 (Barker et al. 2018). The 2017 trench sheds valuable light on the preservation of buried contexts and the potential for the recovery of samples. In all six contexts were identified. 

The lowest contexts show the establishment of the early boundary comprised of distinct plough-horizons at the edge of an area of ploughing, but prior to large-scale clearance of field stone seen in context 307. The three earliest contexts 306 (a soft yellow-orange brown, silty clay, OSL dated as natural, 12,500 BP ± 1800), 305 (a pale brown-grey, slightly clayey soft silt, undated) and 304 (a grey-brown, soft clayey silt, OSL dated as Middle Bronze Age, 3500 BP ± 190) were established against what is likely to be an earth fast ‘grounder’ stone seen in the west section. By the time of the deposit of context 304 the low lynchet had attained a height of 0.46-0.52m.

The addition of the plough soil deposit 303 (a clayey silt; mid brown and soft with occasional small sub angular stones, OSL dated as Middle Iron Age, 2350 BP ±  100) raised the height of the lynchet to 0.64-0.68m at which point it was beginning to attain a flat summit and steeper southern face, still retained by the ‘grounder’ stone but becoming a more prominent terrace in the agricultural landscape.

A distinct change in the pattern of land management and cultivation practice of this slope at South Stream is seen with the formation of the upper context 302 (a browny-black, loose, friable silty loam, OSL dated as Medieval/Twelfth century 870 BP ± 60) a plough-derived soil intermixed with a distinctive deposit of cleared field stone 307 (large angular stones up to 0.4m x 0.25m) , more visible in the east section, showing new plough technology at work with a deeper furrow. The quantity of soil movement downslope increases dramatically, pushing the foot of the new lynchet out at least a metre beyond the ‘grounder’ stone (and burying it in the process) and raising the height of the lynchet to 0.92-0.96m. The final accumulation of the modern turf layer 301 may well have happened in more recent times although the east section displays several angular stones in this upper deposit.

The lynchet was finally surmounted by a wall, of which the base survives (not excavated), probably in the last two centuries of modern farming and enclosure on Skomer.

The implications of these dates for our understanding of the relict archaeology on Skomer are signigficant. In particular the twelfth century AD date radically alters our understanding of the history of farming on Skomer, which had previously been thought to have been largely abandoned save for seasonal grazing and rabbit farming from the fourteenth century onwards.

T. Driver, RCAHMW, October 2024

References:

Barker, L., Davis, O., Driver, T. and Johnston, R. 2012b. Puffins amidst prehistory: reinterpreting the complex landscape of Skomer Island, in: Britnell, W. J. and Silvester, R. J. Reflections on the Past, Essays in Honour of Frances Lynch. Cambrian Archaeological Association. Welshpool. 280-302.

Barker, L., Davis, O., Driver, T. and Johnston, B. 2018. Skomer Island: The excavation of a prehistoric field lynchet associated with the North Stream settlement. Unpublished Report. Royal Commission on the Ancient and Historical Monuments of Wales, NPRN 421796.

Duller, G.A.T. and Roberts, H.M. 2019. Luminescence analysis of samples from Skomer, collected as part of CHERISH – Project 233. Aberystwyth Luminescence Research Laboratory. Aberystwyth University. Unpublished Report.

Driver, T., Duller, G.T., Roberts, H.M., Barker, L., Davis, O. and Johnston, B. 2020. Skomer Island: The excavation and luminescence dating of a Bronze Age, Iron Age and Medieval field lynchet associated with the South Stream settlement. Royal Commission on the Ancient and Historical Monuments of Wales, Unpublished report.