A nautilus fossil from the Pierre Shale of South Dakota perched on top of a matrix of other shell fossil fragments. Several fragments exhibit iridescence from aragonite present in the shell. This display piece sits at 5.2" tall with the nautilus fossil measuring 2".
Fossils found in the Pierre Shale Formation (83-69 million years ago) are part of the Western Interior Seaway which stretched across the Great Plains and much of the Rocky Mountain region, connecting the Arctic Ocean to the Gulf of Mexico. This stretch of the Cretaceous Period between 113-66 million years ago is responsible for many aquatic fossils found in North America.
Locality: Elk Creek, Pierre Shale Formation, South Dakota, USA
Species: Eutrephoceras dekayi
