Small organic bioherms composed of closely packed, carbonate-walled tubes, probably constructed by Sabellariid Worms have been discovered in the " preevaporitic " Messinian strata from Southeastern Spain. These building-rocks are similar to recent bio¬herms in east-central peninsular Florida (USA) and in Mont-Saint-Michel Bay (Western France). These Messinian Sabellariid-reefs are associated with various intertidalites : hardened surfaces, beach rocks, beds with wave ripples and flaser structures, Cardium in living position. Thus fossil Sabellariid¬reefs are growing in lower intertidal area.