The Ordovician in Wyoming, US

Paleontology and geology

Although no rocks of Ordovician age are shown on this map, small exposures of these rocks do occur in the Bighorn and Owl Creek Mountains in the north-central part of the state, as well as in the Black Hills in northeastern Wyoming. The shales and limestones here record the existence of a shallow sea that covered most of the state at this time. Fossils of trilobites, brachiopods, and other marine organisms are found in these rocks.