Marine bivalve bores above present high tide level in a limestone cliff near Ord, southern Skye

Abstract

Bores of marine molluscs above high water mark have been used as evidence for former higher than present sea levels, for instance in the Mediterranean ([Zeuner 1945][1], p. 229). In Scotland, empty bores attributed to the marine bivalve Hiatella arctica (Linne) have been reported up to 2 m above high tide level in limestone at Seafield Point, Loch Kishorn (Fig. 1) by Smith ([1978][2]). She also recorded the presence of the living animal near low water level at this locality. The bores described below were discovered during the field meeting of the Edinburgh Geological Society held in the western Highlands and Skye in May 1984. The foreshore and cliff immediately north of the mouth of the Ord River at Ord (Fig. 1) are formed of cherty dolomitic limestones of the Sailmhor and Eilean Dubh formations of the Lower Palaeozoic Durness Group ([Peach et al. 1910][3]). There is an intertidal rock platform up to 200 m wide which bears traces of moutonee-like forms. These suggest that the platform was glaciated and was therefore cut prior to the last ice movement across the area. The intertidal platform is separated from the base of the cliff by a gently sloping ramp and a poorly developed higher platform. The angle between the latter and the base of the cliff is at a height of c 1 m above high water as indicated by the distribution of black and yellow lichens, seaweeds and land plants. In the intertidal zone the bedrock and limestone boulders lying on . . . [1]: #ref-10 [2]: #ref-6 [3]: #ref-4