Belemnitella from the Ulster White Limestone Formation (c.75 million years old) of Co. Antrim.

These bullet-shaped fossils represent part of an extinct animal closely related to the modern squid. It acted as an internal counterweight located towards the tail of the animal and used to balance the weight of the head.

The first true belemnites appeared early in the Jurassic (200 million years ago), flourishing until their extinction at the end of the Cretaceous (65 million years ago). They are perhaps the most commonly seen fossil in the Ulster White Limestone Formation of Northern Ireland, but also may be found in some of the Lower Jurassic clays in north Antrim.

More belemnites will be added to this page in the near future.