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Overhanging, and shaded vertical, bedrock on the lower shore and in lower shore caves, which is not subject to appreciable wave-surge, characterised by crusts of bryozoans including Oshurkovia littoralis, sponges such as Grantia compressa, Halichondria panicea, Sycon ciliatum and Hymeniacidon perlevis and the ascidian Botryllus schlosseri. On overhangs, the hydroid Dynamena pumila hangs in distinct form from overhanging rock. The barnacles Balanus crenatus, Perforatus perforatus (sometimes at high densities) and Semibalanus balanoides, and the calcareous tube-forming polychaetes Spirorbis spp. and Spirobranchus triqueter can be present as well. Certain species which are generally confined to the sublittoral, including the anemones Metridium senile and Corynactis viridis, may be found in the lower shore caves and overhangs. Littoral species such as Actinia equina are also present. The only algae present are coralline crusts. The list of characterising species partly reflects the variation in the species composition between individual overhangs and caves although this biotope can have a high species richness.