The New Red Sandstone of Raasay and Scalpay, Inner Hebrides

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Abstract
Synopsis: The New Red Sandstone of Raasay and Scalpay contains a series of polymictic conglomerates, greywackes and cornstones between 250 and 300 ft thick. At Rudha na’ Leac, on Raasay, these lithologies are arranged in four distinctive units, each of which shows fining-upwards and contains a sequence of (3) a carbonate horizon (cornstone); (2) fine- to medium-grained greywackes; (1) conglomerates and/or coarse-grained greywackes. The coarser sediments decrease in importance in the upper parts of this sequence, but form a large part of the successions at Eyre (southern Raasay) and on Scalpay. The structure (especially large-scale trough cross-stratification) and content of the coarse sediments, and the similarity between the carbonate horizons described here and those of modern soils suggest deposition in an alluvial fan environment. These rocks are overlain by the Marine Broadford Beds, the base of which is Hettangian in age ( angulata zone). Their stratigraphic position and lithology is similar to the basal Mesozoic of Sweden in which continental facies continue into the Sinemurian.