Perisphinctes Ammonite Fossil

Appears to be a Perisphinctes virguloides ammonite fossil found in Madagascar. Fossil is from the Jurassic Period (201-145 million years ago). Specimen was bought at the bookshop at Museo Civico di Storia Naturale in Milano, Italy.

Prasopora Bryozoan Fossil with Calcite Crystals

This specimen is a mix between a fossil and mineral (calcite crystals). It appears to be Prasopora bryozoan fossil. The fossil dates to the Ordovician Period. It was found in Ripley County, Indiana, USA.

Thanks to Kenny for image.

Saivodus ctenacanthus Shark Tooth Fossil

This appears to be a Saivodus ctenacanthus shark tooth (cladodont) fossil. It was found in Crawford County, Indiana USA. Fossil dates to the Mississippian Period.

Thanks to Kenny for image.