The Secretary of the Interior is authorized, in his discretion and upon submission of evidence of title satisfactory to him, to accept on behalf of the United States, title to the lands referred to in section 410 of this title as may be deemed by him necessary or desirable for national-park purposes: Provided, That no land for said park shall be accepted until exclusive jurisdiction over the entire park area, in form satisfactory to the Secretary of the Interior, shall have been ceded by the State of Florida to the United States.