Basinal calciturbidites and shales of the late Visean Loughshinny Formation, Loughshinny Harbour, County Dublin. These northwards-verging chevron folds are thought to have originated as slump folds moving down the back-tilted footwall block of intrabasinal synsedimentary faults; later burial and Variscide deformation has tightened them. (Photograph by I. D. Somerville.)