It was named after the Pawnee Native American tribe.
Four representatives of the Pawnee tribe traveled from Oklahoma to Nebraska for the dedication ceremony.
The peace pipe, in the form of a tomahawk, belonged to Chief White Eagle of the Pawnee tribe.
But Mr. Adams said the claims of the Pawnee tribe in Nebraska for more than 300 skeletons should be honored.
A Native American from the Pawnee tribe, he is the first full-blooded American Indian to have played in the Major Leagues.
At the site are the remains of a village once occupied by the Kitkehahki, or Republican, band of the Pawnee tribe of Native Americans.
Echo Hawk is a member of the Pawnee tribe.
It was named for the Pawnee tribe, which was relocated to this area between 1873 and 1875.
Other groups, like the Pawnee tribe and some Hawaiian Islanders, have won back human remains, persuading the Smithsonian to sign a formal agreement on the subject last year.
What made his gesture remarkable is that Mr. Gover is himself a member of the Pawnee tribe.