U.S. Interior Secretary Ryan Zinke will recommend no changes to two national monuments located in Washington and Idaho, calling one a “living timeline” while the other remains popular with outdoor enthusiasts, the agency announced on Thursday.

Zinke said that Craters of the Moon National Monument in Idaho and the Hanford Reach National Monument in Washington will be withdrawn from his review for possible changes to their protected status.

“When the president and I began the monument review process we absolutely realized that not all monuments are the same and that not all monuments would require modifications,” said Zinke. “Today I’m announcing that the Craters of the Moon and Hanford Reach National Monuments review process has concluded and I am recommending no changes be made to the monuments."

President Donald Trump in April directed Zinke to study 27 national monuments created since 1996 to gauge whether their size, boundaries and scope conform to parameters in the Antiquities Act.

The act was signed into law by President Theodore Roosevelt and has been used by 16 presidents, including eight Republicans and eight Democrats over the past 111 years.

“As a former geologist, I realize Craters of the Moon is a living timeline of the geologic history of our land on the Great Rift,” Zinke said. “Whether it’s hiking up the alien-like lava flows along the Spatter Cones, or just driving through the scenic loop, there’s a lot to see and learn at this historic location.”

Zinke said Hanford Reach remains important to “sportsmen and women from all over the country,” adding that it offers some of the best hunting and fishing in the region.

“It’s also home to some of the most well-preserved remnants of human history in the area,” Zinke said.

Dozens of other national monuments remain under review, including the Upper Missouri River Breaks National Monument in central Montana. Zinke suggested last month he would recommend making no change to the landmark, though he has recommended that Trump reduce the size of the Bears Ears National Monument in Utah.

Zinke said public comments continue to inform his recommendations.

“These comments, in addition to the extensive on-the-ground tours of monuments and meetings with stakeholders, will help inform my recommendations on the monuments,” Zinke said. “I appreciate everyone who took the time to log-on or write in and participate in our government.”

The public comment period closed on Monday.

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