Two men, Wyatt Clifford Fain, 37, and Payden David Guy Cosper, 31, have been charged by a federal grand jury in Nevada for allegedly damaging historic red rock formations in Lake Mead National Recreation Area.

The charges include aiding and abetting and causing damage to government property. The Justice Department accuses the Henderson, Nevada, residents of pushing rocks off a cliff along the Redstone Dunes Trail on April 7, causing over $1,000 in damage.

The incident, recorded on video and shared on social media, involved red sandstone formations that are 140 million years old.

Fain’s attorney, the Federal Public Defender’s Office, declined to comment, and Cosper’s attorney has not yet responded. John Haynes from Lake Mead National Recreation Area called the act “appalling” and “disgusting.”

Fain and Cosper, who pleaded not guilty at their initial court appearance, face up to 10 years in prison. Their trial is scheduled for October 8.