BERRIASIAN STAGE

standard, worldwide division of Lower Cretaceous rocks and time (the Cretaceous Period began about 144,000,000 years ago and lasted about 77,000,000 years). The Berriasian underlies the Valanginian Stage and is the lowermost stage of the Cretaceous. In Great Britain and elsewhere in northern Europe, the Berriasian is represented by the lower portions of the Wealden Series. The stage is characterized by a distinctive fossil ammonite (mollusk) fauna.