Echioceras sp. Jurassic ammonite fossils collected from the Lower Lias sediments of Charmouth, Dorset. Echioceras is a genus of ammonoid which existed during Lower Jurassic times. These specimens were derived from Lower Lias sediments; Lias being a Middle English term for Limestone but also used to describe the time period between the Rhaetian and the Toarcian stages. These specimens have narrow evolute shells with prominent ribs. They measure between 1.5 and 2 cm in diameter and are supplied in small plastic nags with an information label.