This picture is of a Halysites catenularia (Linnaeus, 1767) chain coral fossil. It existed during the Silurian period. The fossil was foun...

Photo by Laura Dykstra. (c) Field Museum of Natural History . CC BY-NC 4.0 https://fm-digital-assets.fieldmuseum.org/1163/578/P21403_fossil....

This picture is of a Hippocardia cuneus (Conrad, 1840) rostroconch fossil. It existed during the Devonian period. The fossil was found in ...