Outgoing presidents long have made a practice on January 20, their last day in office, of leaving parting gifts. For Lyndon Johnson, his gift to the nation 40 years ago was a national monument that served to protect the Grand Canyon from further dam building.

You see, it was on this date in 1969 that President Johnson, before heading back to Texas and retirement, signed a flurry of papers that created a number of national monuments, among them Marble Canyon National Monument. Some 26,000 acres in size, this monument ran from Lee's Ferry, near the mouth of the Grand Canyon, down to Marble Canyon, which really is where Colorado River floaters first get the feeling that they're entering a canyon of significant size.

At the time the idea was to designate the monument so as to protect the landscape from any more thoughts of building dams in the canyon.

Now, before he turned his back on the Oval Office that day, President Johnson also signed a proclamation to add acreage to two other nearby national monuments -- he tacked on 215,000 acres to Capitol Reef National Monument up north in Utah, and 49,000 acres to Arches National Monument, also in Utah. Of course, those two monuments two years later were redesignated as national parks.

President Johnson also agreed to add 94,500 to Katmai National Monument in Alaska, but then called it a day, declining to accept recommendations to proclaim the Gates of the Arctic National Monument, comprising 4,119,000 acres in northern Alaska; a Mt. McKinley National Monument, also in Alaska containing 2,202,000 acres adjoining the national park; and a Sonoran Desert National Monument in Arizona embracing 911,700 acres.

What became of Marble Canyon National Monument, you wonder? Well, in 1975 it and the Grand Canyon National Monument were added to their neighbor, Grand Canyon National Park.