DENVER (Reuters) – U.S. Interior Secretary Ryan Zinke said on Friday that Colorado’s Canyons of the Ancients archeological site is no longer on a list of more than two dozen national monuments under review by the Trump administration for possible reduction or elimination.

Zinke’s recommendation to keep the Canyons of the Ancients National Monument intact, with no modifications, came a week after he announced that two other sites – Hanford Reach in Washington state and Craters of the Moon in Idaho – had been removed from the list.

Canyons of the Ancients, occupying 178,000 acres in southwestern Colorado along the border with Utah, protects a landscape ranking as one of the highest-density Native American archeological sites in the United States.

It was designated in 2000 by President Bill Clinton, a Democrat. Colorado’s Republican U.S. senator, Cory Gardner, and Republican U.S. Representative Scott Tipton, whose congressional district includes the monument, both applauded Zinke’s decision.

President Donald Trump ordered the Interior Department in April to evaluate 27 national monuments created since 1996 with an eye toward rescinding or shrinking some of them, part of an effort to open more public lands to mining, oil and gas drilling and other development.

A final report on the national monument review is expected in August.

The review also fits in with a larger Trump initiative to reverse many of the environmental protections implemented by his Democratic predecessor, President Barack Obama, that Trump, a Republican, has criticized as hobbling economic growth.

All 27 monuments were designated by executive decree under the 1906 Antiquities Act, which gives presidents authority to preserve federal lands of natural, cultural or scientific significance without congressional action.

The boundaries of one of the sites on Trump’s list, the Grand Staircase-Escalante National Monument in Utah, was modified by Congress in 1998, two years after it was created.

Last month, Zinke said he recommended Trump reduce the size of Bears Ears National Monument in Utah, which Obama designated in the final days of his administration.

Bears Ears, covering 1.35 million acres, is roughly seven and a half times the size of Canyons of the Ancients, though both sites are of strong interest to Native Americans.

Action to scale back or eliminate national monuments is certain to be challenged in court by environmentalists, who assert Trump lacks discretion under the Antiquities Act to do so.

No president has ever rescinded the designation of a national monument, which number 129 across the country.