This is a, polished piece of Kilmluag Limestone from Scotland. This Bathonian limestone, formerly known as Ostracod Limestone, is 167 million years old. Each of the formations in the stone is a fossil Ostracod, a small bivalve arthropod. Ostracods are the most common arthropod in the fossil record. One side of the slab has been cut flat to allow for presentation. This item comes with an acrylic stand.