Cal. Pub. Res. Code § 5869

(a)
1. (1) The department may modify California natural landmark boundaries, or revise information about a California natural landmark, if it determines that modification or revision is necessary. Before considering a proposed modification or revision, the department shall consult with the affected owner.
2. (2)
  1. (A) Federal, state, or local agencies, as well as other public and private organizations or individuals, may suggest to the department modifications of California natural landmark boundaries or revisions of information about a California natural landmark.
  2. (B) The department shall determine the validity of a suggestion made pursuant to subparagraph (A) by applying the state significance criteria in Section 5868 or by conducting additional studies.
(b) Before the department expands the boundaries of a California natural landmark, it shall determine that one of the following apply:
1. (1) There is better documentation of the extent of features of state significance.
2. (2) There was professional error in the original designation of the California natural landmark.
3. (3) The owner of the land included in the proposed expansion has requested that their property be included in the California natural landmark.
(c) If the department determines that expansion of a California natural landmark’s boundaries is appropriate, the department shall use the designation process outlined in Sections 5864, 5865, and 5866 to expand the boundaries. All of the owners of the property into which the boundaries are expanded, as well as the owner of the previously designated property, are required to agree to the expansion.
(d) Before the department reduces the boundaries of a California natural landmark, it shall determine that one of the following apply:
1. (1) There has been loss of integrity of the natural features of the California natural landmark, but not to the extent that requires the rescission of the landmark designation.
2. (2) There was professional error in the original designation of the California natural landmark.
3. (3) A landowner has requested the reduction or rescission of designation.
(e) If the department determines that reduction of a California natural landmark’s boundaries is appropriate, the department shall follow the designation rescission process specified in Section 5870.
(f)
1. (1) If the department determines, with the consent of the owner, that a change in the description of a California natural landmark’s values of state significance is appropriate, the department shall prepare the recommended changes.
2. (2) The director shall review the information and based on that information may approve changes in the description of the California natural landmark’s values of state significance.
(g)
1. (1) The director may approve minor technical corrections to the boundaries of a California natural landmark, as well as other administrative changes in landmark documentation not covered in subdivisions (a) to (f), inclusive.
2. (2) For purposes of paragraph (1), minor technical boundary corrections are those that involve a change in less than 5 percent of the total area of the California natural landmark, and to which the owner of the California natural landmark agrees.
3. (3) The department shall notify the owner of a California natural landmark for which minor technical boundary corrections or other administrative changes in documentation are being considered. Based on the owner’s response to the notification, the department shall determine whether the proposed change is a minor technical correction to landmark documentation that can be made administratively.