Coral fossil in Hansen Cave

Around 340 million years ago, a shallow warm sea covered most parts of the state of Utah. As small marine animals died, their skeletons settled in the sediments. Under immense heat and pressure, the sediments hardened into limestone rock. Upon close inspection, the fossils of these ancient marine animals can be seen in the layers of rock. These fossils can be seen near or inside the cave. The most common types of fossils are Horn Corals, Crinoids, and Brachiopods. These oddly shaped, white deposits in the rock serve as evidence of a constantly changing planet.