The Secretary of the Interior is authorized, in his discretion, to accept as hereinafter provided on behalf of the United States title to the lands referred to in section 403 of this title and to be purchased with the $1,200,000 which has been subscribed by the State of Virginia and the Shenandoah National Park Association of Virginia and with other contributions for the purchase of lands in the Shenandoah National Park area, and with the $1,066,693 which has been subscribed by the State of Tennessee and the Great Smoky Mountains Conservation Association and by the Great Smoky Mountains (Incorporated) (North Carolina) and with other contributions for the purchase of lands in the Great Smoky Mountains National Park area.