Rock particles with a size of between 1/256mm and 1/16mm. Related Articles: The body of a mighty giantFossil fishes of the Old Red Sandstone, ScotlandEssential collectibles (Part 1): Diacalymene trilobitesEssential collectibles (Part 5): Turritella gastropodsPlenty of geological fun at Cornwallis’ Cave« Back to Glossary Index