blue cliff coastline danger Great Britain horizon islet natural nature Pembrokeshire rock sea shore summer united kingdom wales water welsh cave face ripples wild beautiful beauty boat estuary hills home house low manor Mawddach mountains mudflats tide view angry boisterous boulders coast rocks rough spray spume waves distance distant peace quality rills sandbanks scene tidal algae animals creature marine Mollusca periwinkles sealife seaweed snails auk beak bird feet Fratercula arctica puffin Skomer Island webbed wings Armeria gull herring Larus argentatus seagull thrift boats forest green landscape meadow peaceful river tranquil tree architecture beam cog gear Gwynedd historical nostalgia old shaft spar spindle teeth tooth traditional turn watermill waterwheel wheel