There is a clear analogy between the coastal flexured basalts of the Disko Island (W Greenland) and the offshore oceanward-dipping reflectors otherwise observed in the volcanic margins of the Thulean Province. Our tectonic analysis suggests that the coastal flexure is of both syn-magmatic and tectonic origin. It is contemporaneous with dyke injection parallel to the axis of the flexure and to an increase in the extension across the area during the Palaeocene. The proposition that the coastal flexure of Disko Island is syn-tectonic and syn-magmatic throws new light on its origin. We propose that this flexure and, by extrapolation, part of the plume-related seaward-dipping reflectors elsewhere, may correspond to volcanic layers forming a roll-over anticline overlying a continentward-dipping detachment.