The Secretary of the Interior may convey to the Mount Desert Island Regional School District in the State of Maine a portion of the Acadia National Park, formerly owned by John D. Rockefeller, Junior, comprising approximately sixty-six acres (lot 354), and in exchange therefor the Secretary may accept from said school district any property which in his judgment is suitable for addition to the park. The values of the properties so exchanged either shall be approximately equal, or if they are not approximately equal the values shall be equalized by the payment of cash to the grantor or to the Secretary as the circumstances require. Any cash payment received by the Secretary shall be credited to the Land and Water Conservation Fund in the Treasury of the United States. A conveyance of the federally owned lot shall eliminate it from the park.