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New Late Cretaceous epitoniid and zygopleurid gastropods from the Pacific slope of North America
Seventeen species of epitoniid gastropods are discussed from Upper Cretaceous shallow-marine rocks in British Columbia, California, and northern Baja California. Eleven of the species are new: Opalia atra, Opalia cavea, Amaea trifolia, Amaea cerva, Amaea pentzia, Belliscala petra, Belliscala meta, Acirsa alpha, Acirsa beta, Acirsa delta, and Acirsa epsilon. The genera Amaea, Belliscala, and Acirsa have not been previously reported from Cretaceous rocks in this region. Generic assignment, age, and distribution of Opalia? mathewsonii (Gabb, 1864), Belliscala suciense (Whiteaves, 1879), Acirsa obtusa (White, 1889), Acirsa nexilia (White, 1889), and Confusiscala newcombii (Whiteaves, 1903) are discussed. Claviscala sp. is recognized, and it represents the first confirmed Late Cretaceous occurrence of this genus in this region. The very rare and large Zebalia n. gen. suciensis (Packard, 1922), from Upper Cretaceous rocks in Washington and southern California, is an epitoniid-like zygopleurid gastropod and the first Late Cretaceous record of zygopleurids.