The Work

Specialist Report 2004 - Marine Mollusc

Posted by steven on 11/04/2005 at 02:22 PM


Ruby Cerón-Carrasco - University of Edinburgh


The marine molluscs from High Pasture Cave were recovered by sieving and by hand-collection during the excavation. A total of eight contexts contained marine molluscs. The apical fragments of shell were identified to species using standard guides (Campbell & Nicholls1989, Moreno-Nuño 1994a). Frequency was estimated by counting shell apices for gastropods and valve umbos for bivalve species (Moreno-Nuño 1994b). Broken fragments were scanned and an approximate quantification has been given to give a general idea of the presence and importance of the different species found in the assemblage. The species were then quantified in terms of their relative frequency within each sample. This frequency was recorded as:

* = rare i.e. present but in very low quantities (< 5)
**= present i.e. present in low quantities compared to main species (<10)
***= common i.e. present in large quantities similar to other species within a sample
****= present in large quantities i.e. predominant species within a sample


The results of the identification and recording of the marine shell per context is given in the catalogue and presented as Table 1.

Edible periwinkles (Littorina littorea) are found on rocks, stones and seaweed on the middle and lower shores, its shell may be up to 2.5-cm high. Most of the periwinkles recovered at High Pasture Cave were whole specimens measuring from 2 to 3.5 cm in height.

The limpet Patella vulgata, was also common and is found throughout the Scottish coast on all rocky shores. The limpet (Patella vulgata) is a species of major importance in quantitative terms on most littoral shores and in shallow waters (Branch 1985). It is present on all rocky shores from the most sheltered ones dominated by the algae Ascophyllum nosodum L. to the most exposed, mussel and barnacle dominated types.

Common mussel (Mytilus edulis) is found on stones and rocks in estuaries and on exposed shores on rocks often in extensive beds associated with barnacles; its shell may reach up to 10-cm length. Mussel is fragile and it is usually recovered mainly as broken fragments. Most of the mussel shell recovered at High Pasture Cave consisted of broken shell fragments.

The common oyster (Ostrea edulis) is found mainly on shallow water. Its shell may grow up to 10-cm length. Oyster shell recovered at High Pasture Cave was very fragmentary due to its lamellar structure, like that of mussel, its shell therefore tends to fragment and disintegrate more rapidly than other more robust species.

The common cockle (Cerastoderma edule) is found on the lower shore burrowing on sand, mud or gravel on the lower shore and in estuaries, its shell may grow up to 5-cm length.

Fragments of scallop were recovered these included fragments of Great scallop also known as St. James’ Shell (Pencten maximus) which are found on sand and gravel, usually in quite deep water.

The non-edible species consisted of mainly flat periwinkle (Littorina littoralis), which is usually found on seaweed, on bladder wrack (Focus vesiculosus) and on knotted wrack (Ascophyllum nodosum). Rough periwinkle (Littorina saxatilis) is found on rocks and stones, cracks and crevices on the upper and middle shore, it feeds on seaweed. The whelk (Nucella lapillus) is found on rocky shores in the middle shore region, in crevices and among barnacles (on which it preys). The grey topshell (Gibbula cineraria) is found under stones and seaweed on the lower shore.


It is likely that the marine molluscs recovered at High Pasture Cave were originally gathered as foodstuff; shellfish of various types have been used for nutrition and there is considerable regional variation in the uses of shellfish as food throughout the Scottish islands. Although, from early historical accounts it appears that coastal dwellers consumed shellfish not as a rule of preference but as a necessity particularly in times of hardship (Fenton 1984).

Mussel, limpets, periwinkles, cockles and oysters have been used as food throughout Scotland and their remains recovered from sites dated as far back as the Mesolithic. It is rather ambiguous to establish the relative importance of these in the archaeological record but the inhabitants of the Scottish Islands and coastal dwellers around the Scottish coast have used these for nourishment at times of scarcity in the recent past. The ethnographic accounts therefore may show that the farther back in time, the more dependence there was placed on shellfish, and the archaeological evidence may suggest that this may have been the case (Pollard 1994), though perhaps not for every type of shellfish.
It is also interesting to note that shellfish such as periwinkles, limpets and mussel have also been traditionally used as fishing bait and fishing has depended also largely on the seasonal variation in the type of bait (Fenton 1978, 1984).

Some of the non-edible molluscs may have been introduced with seaweed into the cave. The two species of seaweed which flourish well around most of Scotland’s coasts are the intertidal Ascophyllum nosodum, found mainly in the sheltered areas, and Laminaria hyperborea which grows all around the islands but particularly in coasts with extensive shallow sub-tidal rocky areas.


Campbell, A.C. & Nicholls, J. 1989 Seashores & Shallow Seas of Britain and Europe. Ondon: Hamlyn Guides.

Fenton, A. 1978 The Northern Isles: Orkney and Shetland. Edinburgh: John Donald.

Fenton, A. 1984 ‘Notes on shellfish as food and bait in Scotland’. In Gunda B. (ed) The Fishing Culture of the World. Studies in Ethnology, Cultural Ecology and Folklore. Vol. 1. Budapest: Akadémiai Kiadó. 121-141.

Moreno-Nuño, R. 1994a Arqueomalacología. Identificación de Moluscos. Informe no. 1994/18. Laboratorio de Arqueozoologia.Madrid: Universidad Autónoma de Madrid.

Moreno-Nuño, R. 1994b Arqueomalacología. Cuantificación de Moluscos. Informe no. 1994/19. Laboratorio de Arqueozoologia. Madrid: Universidad Autónoma de Madrid.

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