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Upper littoral fringe bedrock, boulders and stable cobbles on very exposed to very sheltered shores which have a blanket covering of the black lichen Verrucaria maura. The winkle Littorina saxatilis is often present. Due to the nature of this biotope it is species poor, but occasionally a range of species may be present in low abundance. These species include the yellow lichen Caloplaca marina and the winkle Melarhaphe neritoides, the barnacles Chthamalus montagui and Semibalanus balanoides or the ephemeral seaweeds Porphyra umbilicalis and Ulva spp. can be present in low abundance (see Ver.B). If one or more of these species is present compare with Ver.B. On northern shores Littorina saxatilis var. rudis can dominate along with the occasional presence of the lichens Verrucaria mucosa and Xanthoria parietina. V. maura can be found overlying stable mud in N. Ireland sea loughs.

Bedrock or stable boulders and cobbles in the littoral fringe which is covered by the black lichen Verrucaria maura. This lichen typically covers the entire rock surface giving a distinct black band in the upper littoral fringe. The winkle Littorina saxatilis is usually present. Two variants are defined which both occur in a wide range of wave exposures. On exposed shores V. maura may occur with sparse barnacles such as Chthamalus spp. or Semibalanus balanoides and may be covered by a band of ephemeral seaweeds such as Porphyra umbilicalis or Ulva spp. (Ver.B). Above Ver.B or on more sheltered shores is a species poor community consisting mainly of V. maura and L. saxatilis (Ver.Ver).

The littoral fringe of very exposed to moderately exposed rocky shores with a sparse covering of the barnacles Semibalanus balanoides and/or Chthamalus montagui over the black lichen Verrucaria maura. Winkles Littorina saxatilis and Melarhaphe neritoides are usually present although M. neritoides tends to be found on more exposed shores. The limpet Patella vulgata is often present though at a low abundance (Occasional). This biotope can be dominated by ephemeral seaweeds including the red seaweed Porphyra umbilicalis, the green seaweeds Ulva spp. or, particulary in the north, microscopic blue-green algae (Cyanophyceae), which overgrow V. maura. The wrack Pelvetia canaliculata (Rare) may also be present, becoming increasingly more common with greater shelter (see PelB). Geographical variation: On northern and eastern shores the barnacle is usually S. balanoides, which is normally restricted to the lower littoral fringe, with a band of V. maura only in the upper littoral fringe. On south-west and western shores the barnacle is usually C. montagui which may extend over the whole of the littoral fringe zone.