Elimia tenera, formerly known as Goniobasis tenera, is an extinct species of freshwater snail with an operculum, in the aquatic gastropod mollusk family Pleuroceridae. This species flourished during the Eocene and is now known only from the fossil record. The genus name Elimia was restored to this species in 1975; formerly it was placed in Goniobasis. Green River Formation deposits Fossilized Elimia tenera shells occur in a region which is now southern Wyoming, northern Colorado and northeastern Utah. The best preserved Elimia tenera are from Lake Gosiute which fossils occur in the Fort Laclede Bed of the Laney Member at outcrops in Sweetwater County, in southwestern Wyoming. 'Turritella agate' The fossils are hosted in chalcedony-rich sedimentary rock. This rock was originally incorrectly called Turritella agate. It was named after the sea snail genus Turritella because of the...