From 25 seismic reflection profiles of the continental margin of the British Isles bordering the Rockall Trough (54° to 57°n Lat.), 15 are selected for description. They reveal a marginal sedimentary succession recording two major phases of subsidence and sedimentation, with an intervening phase of uplift and erosion. Although the Rockall Trough may well date from late Jurassic or early Cretaceous times, a late Cretaceous age of the first phase of subsidence and sedimentation is likely during which a marginal prograding sedimentary series was deposited. The ensuing phase of uplift and erosion is equally tentatively referred to the Palaeocene Epoch. The subsequent transgression and deposition of the overstepping upper sedimentary series is of possible Eocene to Recent date.
There is evidence to suggest that, in addition to these regional phases of subsidence and uplift, the continental margin at 55°20'n Lat. suffered faulting involving major east-west dextral displacement. This occurred prior to the deposition of the older prograding sedimentary series. The sense of movement within the fault zone, and the location and general trend of this zone, are appropriate for correlation with a prolongation or splay of the Great Glen Fault System.