Pachydiscus gulocus Ammonite

The Pachydiscus gulocus ammonite fossil from the Late Cretaceous (68-65 million years ago). Found in South Dakota. On display at the Smithsonian National Museum of Natural History.

Hoploscaphites nicolleti Ammonite

The Hoploscaphites nicoletti ammonite fossil from the Late Cretaceous (68-65 million years ago). Found in South Dakota. On display at the Smithsonian National Museum of Natural History.

Parkinsonia dorsetensis Ammonite

The Parkinsonia dorsetensis ammonite fossil from the Middle Jurassic (174-164 million years ago). Found in England. On display at the Smithsonian National Museum of Natural History.