The typical Silurian rocks are richly fossiliferous, the shales containing trilobites, the sandstones many brachiopods, and the limestones a rich coral and bryozoan fauna.
bryozoan colonies ever recorded.
bryozoan turfs or beds of brittlestars may be dominant.
free-swimming bryozoan colonies ever recorded.
In the sublittoral this steep-sided, wave-sheltered reef is dominated by a dense hydroid and bryozoan turf with anemones and ascidians.