It's been months since Glacier National Park officials concluded after lengthy environmental studies that snowsheds, not 105mm howitzer shells, should be used to protect freight trains from avalanches sliding off the park's southern flanks. And yet Interior Department officials have yet to sign off on that decision.

Never before have, and probably never again will, so many national parks come into existence on the same date. Given birth by the Alaska National Interest Lands Conservation Act were Denali, Gates of Arctic, Glacier Bay, Katmai, Kenai Fjords, Kobuk Valley, Lake Clark and Wrangell-St. Elias national parks.

Former National Park Service Director Fran Mainella says her bosses in the Interior Department in effect tied her hands on the question of recreational snowmobiling in Yellowstone National Park. And now she says science should have the final say in whether snowmobiling continues to be allowed in the park.

Off to the west of Canyonlands National Park proper, Horseshoe Canyon offers a fascinating trip back into prehistory, a time when nomadic tribes would follow the washes through the Southwest's canyon country from camp to camp.