This paper identifies an anomaly between the currently acccpted isobasc pattern for raised shorelines in Scotland. which is a simple ellipsoid centred over the Western Highlands, and current models for the morphology of the Late Devensian ice‐sheet. which show a primary dome in the Western Highlands but a prominent secondary dome over the Southern Uplands. One explanation of this anomaly is that it is an artefact of inadequate shoreline data for south‐west Scotland. To test this hypothesis, altitude data on the Main Rock Platform in the Firth of Clyde area have been collected and analysed. and demonstrate patterns that probably result from the influence of Southern Upland ice. The ice‐sheet models in this area are therefore supp