Belongs within: Clavatulidae. Eosurcula: a brief explosion Published 24 April 2024 The Claiborne Formation is an extensive accumulation of clays and sandstones extending across the southeastern USA, with outcrops in Arkansas, Illinois, Kentucky and Texas. It formed during the middle Eocene, over a series of rapid marine transgressions followed by slower regressions (Eargle 1968). The… Continue reading Eosurcula