GeoGraph - photograph every grid square

Seaweed on the shore

A heavy crop of the Knotted Wrack on intertidal boulders in this early-morning, low-tide view of the shore of Camus Bay. The very prominent black-coloured layer at the high-tide mark is an encrustation by the black-coloured lichen Verrucaria. Above that on rocks only intermittently wet is a yellow-coloured Caloplaca lichen. An altogether superb stratification according to wetting by the sea.