A series of sandstone outcroppings known as the Natural Steps are located just north of the Maumelle Pinnacles and the Fulk Mountains in this state, where a strange earthquake swarm occured in 1982 around Enola, just north of a current swarm around Guy.
The town of El Dorado in this state is the headquarters for Murphy Oil, which produced from the Smackover Formation in this state's south. A series of sandstone outcroppings known as the Natural Steps are located just north of the Maumelle Pinnacles and the Fulk Mountains in this state, where a strange earthquake swarm occured in 1982 around Enola, just north of a current swarm around Guy. The (*) Fayetteville Shale formation is a major gas-producing formation in this state where Toad Suck Ferry is located on this state's namesake river and recent flooding near DeValls Bluff on the White River in this state shut down all traffic on Interstate  ► 40. The only public diamond mine in the US is in, for 10 points, what state that also includes the Boston Mountains and Ouachita Mountains?
The town of El Dorado in this state is the headquarters for Murphy Oil, which produced from the Smackover Formation in this state's south.
Arkansas