East Islay Mesolithic Project - Storakaig & Loch Bharradail

Site stratigraphy and the spatial extent of the Mesolithic occupation

The artefacts at Storakaig were found within the up-throw of a drainage ditch, running approximately north-south and dug into a gently sloping expanse of open moorland, immediately adjacent to the deserted township of Airigh Ghuaidhre. A thirty meter length of the east-facing drainage ditch section, between 112m and 116m OD, was cleaned, photographed and drawn. This revealed a black band of organic-rich deposit (context SK106), sandwiched between peaty sediments (above) and silty clays (below). It contained chipped stone artefacts, coarse stone artefacts, fragments of animal bone and charred plant material. These appeared to be at varying densities along the course of the section. This horizon extended for approximately twelve meters on the higher part of the slope (above 114m OD); it reached a maximum thickness of 270mm, and lensed out at c. 113m OD, where it was replaced by a thin (2cm) horizon of peat within the silty clay. As such, we interpret the organic and artefact rich horizon (SK106) as being the remnants of an in situ Mesolithic occupation, located immediately upslope from an area of boggy ground that resulted in the formation of the peat horizon.

To determine the spatial extent of the Mesolithic occupation deposit and to acquire samples of stone artefacts a test-pit and augur survey was undertaken. Thirty-eight 0.5m square test-pits were excavated on a 10m grid covering a total area of 30m (N-S) by 60m (E-W) centred on the drainage ditch. All sediment from each test-pit above the underlying natural geology (either silty-clay or bedrock) was excavated as a single unit. Thirty litres of sediment from each test-pit (two rubble sacks) was washed through a basket sieve with a 3mm mesh; the residue was then sorted for archaeological materials. The stratigraphy within each test-pit was recorded.

The Mesolithic occupation deposit (context SK106) was only found within the test-pits located 10m west from the ditch; elsewhere peaty top-soil and loamy-sub-soil was located directly on the underlying geology. With few exceptions, however, all test-pits contained stone artefacts.

In light of the cultivation of the area by the past inhabitants of the Airigh Ghuaidhre township, only those stone artefacts found within the Mesolithic occupation horizon (SK106) can be assumed to be in situ. Four test-pits revealed archaeological features: two were modern, the remnants of a slate wall and a still active stone-built field drain; two are indeterminable of date, a stake-hole and shallow pit (or the terminus of a linear feature).

To ascertain the distribution of the occupation horizon on the eastern side of the ditch, an augur survey was undertaken. Nineteen cores were taken at either one metre or two metre intervals up to 10m east of the trench. The lithostratigraphy of each core was recorded and the occupation horizon was found within nine of them. From the test-pitting, auguring and the ditch section, we estimate the surviving Mesolithic occupation horizon to cover a sub-elliptical area approximately 17m by 20m. This coincides with the area delimited by test-pits with particularly large numbers of chipped stone artefacts: 75% of the 4362 recovered came from just eight of the test-pits, all located within the bounds of the elliptical area where the occupation horizon is inferred to exist. Although a geophysical survey was undertaken, this failed to identify any anomalies likely to be Mesolithic features within this occupation area.

Here we see the occupation horizon within the 3x3m trench at Storakaig being excavated. The trench had been gridded into 0.5m squares so that we could maintain some degree of spatial control over where the artefacts had come from. Samples were taken from this black deposit for wet sieving and produced large quantities of animal bone fragments and charred hazelnut shells as well as stone artefacts.

Recovering archaeological samples and material for radiocarbon dating from the occupation horizon
A 3m by 3m trench was excavated at 114m OD within the area of the occupation deposit, the eastern edge of this trench being provided by the ditch section (20). Following removal of the peaty top-soil (context SK101) the underlying sub-soil (SK102) had a 0.5m grid imposed across its surface and 10 litres of sediment was taken from each of the resulting 36 squares for wet sieving through a 3mm mesh; a further five litres was taken for sieving through 4mm/2mm/1mm/0.5mm meshes in laboratory conditions.

The remaining sediment within each square was sorted by hand for archaeological materials. Removal of the subsoil in this manner exposed the surface of the occupation deposit (SK106) that appeared entirely homogeneous across the extent of the trench. This was sampled in the same manner, although time constraints meant that only 10 of the 36 squares of this horizon could be excavated.

The stone artefacts
This small scale fieldwork generated a large sample of chipped stone artefacts: 4362 from the test pits, 4184 from horizon SK102 in the 3m by 3m trench, and 1969 from the underlying and only partially excavated horizon of SK106. Artefacts that were greater than 5mm in size coming from the trench (contexts SK102 and SK106) and from the occupation horizon (SK106) within the two test-pits in which this was found, were catalogued according to their artefact class, raw material and condition. Artefacts from these contexts less than 5mm were counted and their raw material recorded. The artefacts coming from the test-pits were counted and scanned. The collection as a whole is clearly Mesolithic with no significant sign of more recent periods as would be denoted by distinctive Neolithic or Bronze Age artefacts. Diagnostic Mesolithic artefacts such as microliths, bladelets, microburins and platform cores are all present, the large majority being made from flint with some use of quartz and occasional other materials. There are some interesting differences between the assemblages from the occupation horizon (SK106) and that from the non-occupation horizon contexts in the test-pits. The latter appears to have more traditional 'narrow-blade' elements with numerous scalene triangles and sub-pyramidal cores. Diagnostic Mesolithic elements and signs of tool-making itself are relatively rare within the occupation horizon (SK106), which also has a higher frequency of artefacts made from quartz (45%) rather than flint (11%). If this difference is real, then there are two possible interpretations that will need to be tested by further excavation: either there are two cultural phases at the site or there is spatial variability within the site activities resulting in the deposition of contrasting chipped stone debris.

Two hundred and seventy artefacts of coarse stone were recovered from Storakaig. These included spherical pebbles which had most likely to have been used as hammerstones. Some of these rounded pebbles had signs of abrasion, or 'plecking', on their surfaces and have been identified by Dr Ann Clark as a distinctive coarse stone tool type for the Mesolithic of western Scotland. Elongated pebbles which are traditionally described as 'limpet hammers' but were most probably used for numerous functions, and large flakes of stone were also part of the coarse stone tool assemblage.

The animal bone
Several thousand fragments of animal bone were recovered from Storakaig. These were all found within the occupation horizon (SK106) and collected by either hand picking from the deposits or extracting from the wet sieve residues. Samples for the laboratory sieves (4mm/2mm/1mm/0.5mm) remain to be processed. The majority of fragments are less than 10mm making identification of diagnostic anatomical features extremely difficult, a challenge that is exacerbated by distortion of exposed surfaces by burning.

All pieces over 2mm were examined as to their degree of erosion, each piece being assigned a score between 1 (excellent) to 5 (poor). The majority were found to be of a good condition, although almost all were cracked and calcined, indicating exposure to high temperatures which is the likely cause of the fragmentation. This may have occurred during cooking but is more likely a consequence of being placed directly into hot ashes, either simply as discard or possibly as a source of fuel.

An attempt was made to identify each fragment of bone to species and anatomical part. Fifty-two pieces were identifiable to species. More than half of these are from roe deer (Capreolus capreolus); several are from red deer (Cervus elaphus) with wild boar (Sus scrofa) and badger (Meles meles) represented by single specimens. Almost all of the identifiable pieces are foot bones, especially carpals and phalanges, although pieces of femur, tibia and tarsal bones are present.

(left) Tiny foot bones from red deer (Cervus elaphus). Bones from the feet of variety of different animals were found preserved in the Mesolithic horizons at Storakaig and Rubha Port an t-Seilich. These are likely to derive from the waste of domestic fires. Foot bones are commonly encountered in archaeological hearth deposits while other skeletal components have rotted away. This is because the small bones of the foot are denser than other bones, and tend to preserve better. (middle)A foot bone (3rd phalanx) from wild boar (Sus scrofa). Bone fragments from wild boar were found both at Storakaig and Rubha Port an t-Seilich. (right)Burnt bone from the foot (2nd phalanx) of a badger (Meles meles) found in the black occupation horizon at Storakaig. Were the Mesolithic inhabitants of Storakaig hunting, killing and consuming badgers along with larger mammals such as wild boar and deer?

The plant remains
The charred plant material included 7 fragments of charcoal from four test-pits distributed across the testpitted area, while 41 fragments of charred hazelnut shell were recovered from two test-pits located to the west of the ditch at c. 114m OD. These were collected either by hand-picking or sieving through a 3mm mesh on site. All the charred plant remains from the test-pits were highly fragmented and less than 4mm in size. Approximately 1500 fragments of charred hazelnut shell were recovered from the occupation horizon (SK106) either by hand-picking or wet sieving on site using a 3mm mesh with a further c. 90 fragments collected in sieves (4mm, 2mm, 1mm, 0.5mm) in the laboratory (30, 31). Twenty five fragments of wood charcoal were also collected from the occupation horizon using the same methods of recovery. These pieces were well-preserved and larger than 4mm in size and on-going work will determine the source of wood to provide information about the composition of local woodland. The overlying sub-soil (SK102) contained less charred plant remains with 6 fragments of charred hazelnut shell and c. 15 pieces of wood charcoal collected either by hand-picking or sieving through a 3mm mesh on site. Charred stems and seed heads of Juncus spp. (rush) were also recovered from the sub-soil.

Charred hazelnut shells are frequently encountered on Mesolithic sites in western Scotland. Hazelnuts provided a staple ingredient in Mesolithic diets served either roasted or mashed into a paste. While the nutritious nuts were eaten, their shells were discarded in domestic fires as waste or perhaps used to add fuel to the fire. Furthermore, the charcoal preserved on site is likely to derive from wood used to fuel these domestic fires.

Loch Bharradail
A location to the immediate south of the standing water within Loch Bharradail was selected for a testcore. A depth of 6.5 metres was reached using the available coring equipment - with no sign that the base of the peat was being approached. A sample of peat from the base of the core (6.5m) was radiocarbon dated to 2020 ± 40 14C BP (Beta-288422, 2100-1880 cal BP). This indicates a rapid accumulation of peat within the basin, suggesting that pollen and other indicators will be able to provide a detailed record of the recent environmental history, one influenced by climate change, ecological succession and human activity. Whether the Loch Bharradail deposit will also reach back into the Mesolithic period remains to be determined. This will require a further programme of coring along transects perpendicularly aligned across the basin to determine the position of the deepest peat deposits. Once established, multiple cores will be collected for radiocarbon dating and potentially detailed palaeo-environmental analysis.

Main Sections of the East Islay Mesolithic Project

Islay History | Standing Stones | Finlaggan | Islay Carved Stones | The Campbells | Walter Campbell | John Francis Campbell | Islay Clearances | Leaving Islay | Islay Genealogy | Islay in 1703 | 1869 Baptist Letter | Islay Shipwrecks | Exmouth Tragedy | Troopship Tuscania | Otranto and Tuscania | Dougie MacDougall | Ferry History | Cultoon and Ballinaby | Sunderland Flying Boat Tragedy | Kilchoman Bards


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