Shingle beaches, banks and ridges form as storm waves throw pebbles higher and higher up the beach until they reach the point where the backwash from the waves can no longer reach them. It is on these higher and relatively stable ridges that the ‘Annual vegetation of drift lines’ (1220)’ habitat develops: a habitat that is listed on Annex I of the EC Habitats and Birds Directive. In Wales, this habitat is characterised by the presence of yellow-horned poppy (Glaucium flavum) and sea kale (Crambe maritima), with the best example found on the shingle bank at Cemlyn Bay in Anglesey (see image). Less well defined examples can also be found at Aberthaw and Newton Beach in south-east Wales, amongst other places.