" There, below the cliffs, is a bay of sand where the rocks stand up like the fangs of wolves, and no boat or swimmer can live when the tide is breaking round them. To right and left of the bay the sea has driven arches through the cliff. The rocks are purple and rose-coloured and pale as turquoise in the sun, and on a summer’s evening when the tide is low and the sun is sinking, men see on the horizon land that comes and goes with the light. It is the Summer Isle, which (they say) floats and sinks at the will of heaven, the Island of Glass through which the clouds and stars can be seen, but which for those who dwell there is full of trees and grass and springs of sweet water . . .’ The "

― Mary Stewart , The Hollow Hills (Arthurian Saga, #2)