There is authorized to be appropriated, out of any money in the Treasury not otherwise appropriated, the sum of $20,000, which shall be available until expended for the purposes stated in section 69 of this title: Provided, That at such time as the Smithsonian Institution is satisfied that any State, educational institution, or scientific organization in any of the United States is prepared to contribute to such investigation and when, in its judgment such investigation shall appear meritorious, the Secretary of the Smithsonian Institution may direct that an amount from this sum equal to that contributed by such State, educational institution, or scientific organization, not to exceed $2,000, to be expended from such sum in any one State during any calendar year, be made available for cooperative investigation: Provided further, That all such cooperative work and division of the result thereof shall be under the direction of the Secretary of the Smithsonian Institution: Provided further, That where lands are involved which are under the jurisdiction of the Bureau of Indian Affairs or the National Park Service, cooperative work thereon shall be under such regulations and conditions as the Secretary of the Interior may provide.