Land subject to determination under section 3(e)(1) of the Act will be subject to conveyance to Native corporations if they are determined to be public lands under this subpart. If the lands are determined not to be public lands, they will be retained by the holding agency. The Bureau of Land Management shall determine:

(a) Nature and time of use.

(1) If the holding agency used the lands for a purpose directly and necessarily connected with the Federal agency as of December 18, 1971; and

(2) If use was continuous, taking into account the type of use, throughout the appropriate selection period; and

(3) If the function of the holding agency is similiar to that of the Federal agency using the lands as of December 18, 1971.

(b) Specifications for area to be retained by Federal agency.

(1) Area shall be no larger than reasonably necessary to support the agency's use.

(2) Tracts shall be described by U.S. Survey (or portion thereof), smallest aliquot part, metes and bounds or protraction diagram, as appropriate.

(3) Tracts may include:

(i) Improved lands;

(ii) Buffer zone surrounding improved lands as is reasonably necessary for purposes such as safety measures, maintenance, security, erosion control, noise protection and drainage;

(iii) Unimproved lands used for storage;

(iv) Lands containing gravel or other materials used in direct connection with the agency's purpose and not used simply as a source of revenue or services. The extent of the areas reserved as a source of materials will be the area disturbed but not depleted as of the date of the end of the appropriate selection period; and

(v) Lands used by a non-governmental entity or private person for a use that has a direct, necessary and substantial connection to the purpose of the holding agency but shall not include lands from which proceeds of the lease, permit, contract, or other means are used primarily to derive revenue.

(c) Interest to be retained by Federal agency.

(1) Generally, full fee title to the tract shall be retained; however, where the tract is used primarily for access, electronic, light or visibility clear zones or right-of-way, an easement may be reserved in lieu of full fee title where the State Director determines that an easement affords sufficient protection, that an easement is customary for the particular use and that it would further the objectives of the act.

(2) Easements reserved in lieu of full fee title shall be reserved under the provisions of section 17(b) of the Act and § 2650.4-7 of this title.