On the Moiero River (north central Siberia), flowing past the Anabar Uplift, there are numerous, unusual calcimicrobial Angarella -soanitid sponge reefs 6-7m in diameter and 2-3m high in the Bugarikmin Fm. (?Caradoc-Ashgill) which are illustrated by Myagkova et al. (1977): such reefs appear to be endemic to this area. 