DENVER — The federal government's rush to develop energy on millions of acres of federal land in the West is leaving vast natural and cultural resources languishing, the head of the National Trust for Historic Preservation says.

Richard Moe, head of the National Trust, said the nation is in danger of losing a critical part of its heritage as archaeological sites and artifacts in such places as Colorado's Canyons of the Ancients and Utah's Nine Mile Canyon lie undocumented and unprotected.

The misnamed Nine Mile Canyon stretches for 75 miles from around Price to Myton, Duchesne County. According to Jerry Spangler, an Ogden archaeologist who is now the director of the Colorado Plateau Archaeological Alliance, a 45-mile section hosts many examples of ancient Indian rock art.

Tens of thousands of rock art images are in Nine Mile Canyon, he said.

About 1,000 archaeological sites with rock art, granaries or other cultural resources have been documented, Spangler added, "and we estimate that that represents only about 10 percent of the total."

In a report to be released today, the National Trust says only 17 million acres of the 262 million acres that the Bureau of Land Management oversees in 12 Western states have been surveyed to identify cultural resources.

"The American experience, the real American experience, didn't begin at Jamestown or Plymouth Rock. It began here in the West, at places like Canyons of the Ancients and Agua Fria" in Arizona, Moe said in a prepared statement.

Concerns about the BLM's ability to preserve that past led the private, nonprofit National Trust to declare the entire National Landscape Conservation System, created by the Clinton administration, to be endangered. The conservation system covers about 26 million acres of BLM land and includes national monuments, conservation areas, historic and scenic trails.

"There are people all over the West who love these sites and are working hard to protect them," Moe said in a phone interview last week with The Associated Press. "But you can't protect them if you don't know where they are."

Moe said the BLM doesn't have the money or staff to survey much of its land or adequately patrol and protect such resources as ancient cliff dwellings and petroglyphs from the growing number of off-road vehicles and other threats.

At the 164,000-acre Canyons of the Ancients in southwestern Colorado, only one ranger is in charge of law enforcement. More than 6,000 archaeological sites have been recorded there, and thousands more are believed to exist.

BLM spokeswoman Celia Boddington said the agency's finances are more complex than portrayed in the report. She said employees funded by one program often help with others, including cultural preservation.