Asteroceras confusum & Promicroceras planicosta ammonite specimens attached to matrix collected from the Jurassic, Lower Lias rocks of Charmouth, Dorset. The Asteroceras specimen measures 4 cm in diameter; its shell has been partially agatised and it exhibits prominent, sharp ribs with a well pronounced keel. Promicroceras in an extinct genus of ammonite which can be found in European Upper Sinemurian marine strata; it is particular abundant within the Jurassic marine rocks of Southwest England. This Promicroceras specimen measures 1 cm in diameter; it exhibits an evolute, strongly ribbed shell which has been completely agatised. Supplied in a small plastic bag with an information label.