When title to the sites of Fort Boonesborough, Boones Station, Bryans Station, and Blue Licks Battlefield, in the State of Kentucky, comprising noncontiguous tracts to be united by a Memorial Highway, together with such historical structures and remains thereon, as may be designated by the Secretary of the Interior as necessary or desirable for national-monument purposes and for the proper commemoration of the valor and sacrifices of the pioneers of "the West", shall have been vested in the United States, said areas and improvements shall be designated and set apart by proclamation of the President for preservation as a national monument for the benefit and inspiration of the people, and shall be called the "Pioneer National Monument."