Rocks on Worm’s Head Causeway (4)

In the earlier post Rocks on Worm’s Head Causeway (3), the photographs illustrated the sharp, jagged nature of the protruding inclined rows of limestone that outcropped close to the shore. However, further out on the causeway, the rocks have developed a softer outline and smoother surface texture where the waves and their pebble load have worn away the rough edges of the stone. The wear is not even for each exposed layer of Carboniferous limestone. Some strata are composed of materials in such a way as to be either easier or more resistant to weathering and erosion.

The rocks more distant from the shore lack the black, orange, and yellow coloured lichens that encrust the stone in the intertidal areas. The gullies tend to be totally bare but the upstanding rocks can be covered with greeny-grey living layers of acorn barnacles or colonies of blue-black mussels.

The smooth bare rocks vary in colour too. Light buff or palest blue-greys predominate. Frequently, the boulders and strata are tinted with pink, or streaked with red hues in the cracks and crevices that intersect them.