The major biostrome builders are medium-sized coralline sponges, Demospongea and Calcarea, encrusted by smaller sponges, tube worms, sessile foraminifera, calcareous algae - Archaeolithoporella - and Shamovella - Tubiphytes-, all of which are typically covered by microbial crusts. The biostromes are characteristically composed of bafflestone and bindstone, incorporating sporadic framestone.
Narrowbelts of floatstone surround the buildups, and sponge debris is also present in lenseswithin the mud matrix between metazoan bafflestones