Turritella is a genus of medium-sized sea snails with a cow-like and an operculum, marine gastropod mollusks in the family Turritellidae. They have tighly coiled shells, whose overall shape is basically that of an elongated cone.
The shells are quite frequently found as fossils, and the carbonate stone made from large quantities of Turritella shells is often referred to as "Turritella limestone", or, if silicified, "Turritella agate". Both varieties of this stone are commonly sold as polished cabochons.
The Turritellenplatte of Ermingen ("Erminger Turritellenplatte" near Ulm, Germany) is situated in the northern part of the North Alpine Foreland Basin (NAFB), and it is famous for its superabundance of Turritella turris gastropod shells within its sediments.