Preservation of historical and archeological data : hearings before the Subcommittee on National Parks and Recreation of the Committee on Interior and Insular Affairs, House of Representatives, Ninety-second Congress, second session on H.R. 735, to amend the Act of June 27, 1960 (74 Stat. 220), relating to the preservation of historical and archeological data : hearings held in Washington, D.C., September 11 and 12, 1972