Two Nevada men accused of damaging rock formations estimated to be 140 million years old at the Lake Mead National Recreation Area back in April are facing charges and potential prison time.

Wyatt Clifford Fain, 37, and Payden David Guy Cosper, 31, each face a federal indictment for one count of injury and depredation of government property and one count of aiding and abetting, The Associated Press reported. 

A trial has been set for Oct. 8, and the men could each face up to 10 years in prison if convicted, the U.S. Department of Justice said. 

Fain and Cosper, both of Henderson, were arrested by the U.S. Marshals Service and made their first court appearance on Friday. They both pleaded not guilty and were released on a personal recognizance bond, the Las Vegas Review-Journal reported.

CAR PLUNGES OVER CALIFORNIA'S DEVIL'S SLIDE CLIFF, 3 VICTIMS IDENTIFIED

Jutting rocks and natural caves carved out by erosion and weathering at Lake Mead's Redstone Trail. (A. Harrison/NPS)

The men allegedly can be seen on video posted to social media pushing boulders until they fell in front of a screaming little girl. That happened on April 7 on the Redstone Dunes Trail. 

The trail is 1.1 miles round trip, according to the National Park Service (NPS). The rocks and caves in the area are a result of erosion and weathering.

HISTORIC COVERED BRIDGE CLOSED AFTER TRUCK FALLS THROUGH, CREATING GAPING HOLE

Lake Mead is seen from Sand Island, which is no longer an island, as unprecedented drought reduces Colorado River and Lake Mead to critical water levels on Sept. 18, 2022 in Lake Mead National Recreation Area, Nevada. (David McNew/Getty Images)

"Over time, geological forces turned the loose dunes into hard sandstone," the NPS website says. 

The Lake Mead National Recreation Area, just outside of Las Vegas, draws around 6 million visitors every year and spans 2,344 square miles of mountains and desert canyons.

Rugged eroded Volcanic basalt near Lake Mead in the Lake Mead National Recreation Area, Nevada. (Jon G. Fuller/VW Pics/Universal Images Group via Getty Images)

Authorities said staffing levels mean park officials often rely on the public to also keep watch over resources within park boundaries.

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The damage as a result of the rock formations being pushed over a cliff edge is estimated at more than $1,000.

The Associated Press contributed to this report.