Where any Indian entitled to allotment under existing laws shall make settlement upon any surveyed or unsurveyed lands of the United States not otherwise appropriated, he or she shall be entitled, upon application to the local land office for the district in which the lands are located, to have the same allotted to him or her and to his or her children in manner as provided by law for allotments to Indians residing upon reservations, and such allotments to Indians on the public domain as herein provided shall be made in such areas as the President may deem proper, not to exceed, however, forty acres of irrigable land or eighty acres of nonirrigable agricultural land or one hundred sixty acres of nonirrigable grazing land to any one Indian; and when such settlement is made upon unsurveyed lands the grant to such Indians shall be adjusted upon the survey of the lands so as to conform thereto, and patent shall be issued to them for such lands in the manner and with the restrictions provided in sections 348 and 349 of this title. And the fees to which the officers of such local land office would have been entitled had such lands been entered under the general laws for the disposition of the public lands shall be paid to them from any moneys in the Treasury of the United States not otherwise appropriated, upon a statement of an account in their behalf for such fees by the Secretary of the Interior or such officer as he may designate, and a certification of such account to the Secretary of the Treasury by the Secretary of the Interior.