The structural evolution of north wales

The Caledonian structures of North Wales were foreshadowed by Pre‐Cambrian structures. A feature of the Caledonian pattern is a deflection of cleavage and fold trends from north‐south, as in Merionethshire, to east‐west, as in Denbighshire. The axis of this deflection trends northwest—southeast from Shropshire to Anglesey; it appears to be wrenched sinistrally along the Bala fault. The vergence of cleavage and folds is generally towards the east and south. Intensity of deformation increases from the foreland (Shropshire) to Anglesey. Late‐Caledonian granite and dolerites are discussed in relation to deformation. Post‐Caledonian events are briefly reviewed.