Hercynella is a genus of fossil bivalves of late Silurian or (more commonly) Early Devonian age, found in Europe, North America, western Asia, North Africa and Australia. The name was also invalidly applied to a genus of moths now known as Tulaya.Species were originally thought to be patellid gastropods and it was not until 1950 that H. & G. Termier realised that they were bivalves.