This habitat type occurs on wave-sheltered, variable salinity bedrock and cobbles, subject to moderately strong to weak tidal streams. This complex contains a suite of sponges able to tolerate the variable salinity conditions like Hymeniacidon perleve, Suberites ficus, Halichondria panicea, Halichondria bowerbanki, Cliona celata and Leucosolenia botryoides. The barnacle Balanus crenatus is frequently recorded in this complex. A sparse hydroid/bryozoan turf composed primarily of Nemertesia antennina, Nemerteis ramosa, Plumularia setacea, Alcyonidium diaphanum and Bugula plumosa is often recorded. Other species recorded are the ascidians Clavelina lepadiformis, Morchellium argus and Dendrodoa grossularia, the anemones Metridium senile and Sagartia troglodytes, the starfish Asterias rubens and the crab Carcinus maenas.