Paleontology and geology
Ordovician rocks occur at the surface only in the Arbuckle Mountains in south-central Oklahoma and in the Wichita Mountains in the southwestern corner of the state. A shallow sea covered all of Oklahoma during much of the Ordovician. Brachiopods and trilobites are common fossils found in the limestones of the Arbuckle Mountains. Corals, snails, and clams can also be found.