Turritella

Turritella is a genus of medium-sized sea snails with an operculum, marine gastropod mollusks in the family Turritellidae.^[3]

The name Turritella comes from the Latin word turritus meaning "turreted" or "towered" and the diminutive suffix -ella.^[4]

Valid species within the genus Turritella are listed below. Fossil species are marked with a dagger "†".

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.

One variety of "Turritella agate", that from the Green River Formation in Wyoming, is a fossiliferous rock which does indeed contain numerous high-spired snail shells. However, contrary to the common name, these snails are not in the marine genus Turritella, instead they are freshwater snails in the species Elimia tenera, family Pleuroceridae from the Eocene epoch.^[90] The rock in which these snail shells are so abundant varies from a soft sandstone to a dense chalcedony. This dense silicified rock is popular with gem and mineral hobbyists, as well as with New Age practitioners.

The Erminger Turritellenplatte ("Turritella plate of Ermingen") near Ulm, Germany^[91] is a rocky outcrop situated in the northern part of the North Alpine Foreland Basin. It is famous for its superabundance of Turritella turris shells within its sediments^[92] and dates from the Burdigalian.

A medium sized sea snail in a genus India

Numerous shells of a Turritella species washed up on the beach at Playa Grande, Costa Rica

Detail of a fossilized Turritella tricarinata

Fossil specimens of Turritella incrassata

Turritella agate, in which the fossils are a different genus