Monument record MHG29334 - Glassknapper's cave - Geodha Smoo, Durness

During excavations in 1992 by GUARD to record eroding midden deposits in Smoo Cave (see MHG11597) the opportunity was taken to investigate its wider environs. This brought to light the presence of a further shell midden some 50m to the northwest of the main cave entrance. Like the deposits in the main cave this site had undergone serious erosion, this time marine in nature. The deposits were noted as being of considerable extent, with the eroding section some 9m long and around 2.5m deep. It revealed several deposits rich in marine shells and butchered animal bone. Following the completion of the assessment a quern stone was found eroding from the section. It was recommended that the site be investigated before it was totally lost to the sea. <1>

During spring 1995 GUARD were commissioned by Historic Scotland to carry out rescue excavation of the coastal midden deposits identified in 1992 to the northwest of Smoo Cave. The deposits were located across the mouths of two small adjoining caves which were situated in the western wall of the narrow, canyon-like inlet through which Alt Smoo flows. The caves were named by excavators as a means of preventing confusion with the larger cavern - Glassknapper's so-called because of finds of bottle glass which at first sight looked as though they had been knapped (they had not) and Antler Cave (see MHG29332) after unmodified red deer antler was found in the deposits. When the section was cleaned back it became apparent that there was a difference between the deposits of the two caves. The southern cave (Grassknapper's Cave) appeared to contain a far more complex series of deposits. The deposits in the northern cave (Antler Cave) were less well defined and varied.

Excavation in Glassknapper's Cave carried out over 4 weeks revealed deposits of accumulated midden, which in places reached a depth of around 2m, containing concentrations of marine shells, including oysters and limpets and animal bone, which included deer, cattle and sheep. Quantities of fish bone were also present, at least some of the larger pieces probably representing cod. Pottery sherds were found at various levels and suggest Late Norse and post-Norse activity in the upper levels and possible Iron Age activity in the lower levels. Of most interest were a number of organic artefacts, which included a peg carved from antler, a bone spatula and a broken bone needle, with a perforated round head. A number of square-headed rivets and iron slag strongly suggest that boats were hauled up onto the beach for repair. No sign of earlier prehistoric activity was identified, with the cave's location on present shoreline strongly suggesting its total innundation for much of the Mesolithic. Analysis of faunal remains and artefacts is now under way. <2>

The full published report for the 1995 excavations presents detailed analysis of the environmental samples recovered from the cave deposits. The internal deposits on the whole consisted of numerous thin layers and lenses of organic material, clays and silts, ash, charcoal, crushed shell, animal bones and washed deposits. It proved impossible to excavate each of these deposits individually and to overcome this problem a column sample was removed from the deepest portion of the deposits with samples bagged in approximately 0.02m spits. Analysis of these samples revealed a wide variety of plant remains with recovered charcoal providing three radiocarbon dates collectively dating to AD 770-1160. There was no convincing evidence for substantuial structural elements although two concentrations of stones appeared to represent artificial arrangements. One contained a beach pebble hammerstone and several sherds of wheel-thrown, medieval pottery. Three sherds of pottery, bearing some similarity in form and fabric to various assemblages from the Northern Isles were ascribed an Iron Age date. Several sherds were similar to Norse assemblages from elsewhere in northern Scotland, including Freswick Links and Kirkwall. A large variety of fish species was represented in the samples, which included young siathe and pollock, mature cod, hadock, ling and herring. Evidence for both inshore and deep sea fishing was present in these samples, with the fish being caught to be consumed on site. Bones from seabirds were also present, as were the largest number of mammal bones from any of the investigated caves. These were from both domesticated and wild animals including cattle, sheep, pigs, deer and seal pups, many bearing cut marks. There was also evidence that long bones and red deer antlers were processed into artefacts in the cave. Common limpet and common mussel (much of it burnt), along with whelk, oyster, edible periwinkle and crab were also present. Most were probably consumed as food although some could have been used as fishing bait. Plant evidence recovered from the samples included small carbonised oat and hulled barley along with field weeds which indicated that grain was processed on site. There was also evidence that peat was collected and brought to the cave for use as fuel or possibly to build or enhance a barrier across the mouth of the cave. <3>

The cave was visited during a rapid coastal zone assessment of a stretch of the north Sutherland coastline by GUARD in 1997. The assessment had been commissioned by Historic Scotland. The survey noted that wave action was continuing to erode the remaining deposits. See report for full detail. <4>