LAS VEGAS — A prominent sandstone arch at Valley of Fire State Park in southern Nevada has collapsed.

Park rangers said it appears Natural Arch was claimed by forces that will eventually destroy about 300 others in the park: gravity and erosion.

They said horseback riders notified them about the damage Wednesday, and no one has reported seeing it fall. While it's unclear exactly why and when the arch collapsed, there's no evidence of vandalism, rangers added.

"Maybe someone tried to take a picture on the rock, which we don't recommend, but there's nothing here that proves this was done on purpose," park supervisor Jim Hammons told the Las Vegas Review-Journal.

The arch is along the Natural Arch Trail near the park's east entrance. Standing on a rock formation about 40 feet off the ground, the arch was nearly 6 feet tall and 5 feet across.

About a decade ago, another arch in the park, Mosquito Rock, collapsed after a combination of wind and rain during a storm.

Hammons said the same combination could have contributed to the collapse of Natural Arch, located about 55 miles northeast of Las Vegas.

"It's not a strong rock," he said. "That's why we really don't have rock climbing out here. After enough water this stuff can break like a dirt clod."

The collapse left piles of crumbled, powdery red remains on Natural Arch's northwest side and a larger chunk of rock on the nearby trail.

The arch, which once resembled a dragon feeding its young, now appears more like a crescent. The long, rocky span that some hikers nicknamed the "dragon" is no more.

Like others in the park, Natural Arch was formed when sandstone was whittled down over time into its distinctive and photogenic formation.