California Code, Public Resources Code - PRC § 3915

(a) The following are the only monuments which may be used pursuant to this chapter:

(b) Where, by reason of precipitous ground, it is impractical or dangerous to place a monument in its true position, a witness monument may be erected as near thereto as the nature of the ground will permit and marked so as to identify the true position.

(c) Where, by reason of working the claim, it is impractical or dangerous to maintain a monument in its true position, a witness monument shall be erected as near thereto as the nature of the ground will permit and marked so as to identify the true position.

(d) Any person using on January 1, 1992, or who has previously erected, any monument or object other than those defined in this section for the purposes of this chapter shall have until January 1, 1995, to comply with this section or remove those monuments which are not in compliance.

(e) Within 180 days of abandonment, relinquishment, or loss of a claim, in effect on January 1, 1992, all monuments pertaining to that claim shall be permanently removed by the locator.  A person who violates this subdivision shall be subject to a fine of not more than fifty dollars ($50) for each monument which is not removed and additionally liable for any cost incurred by the federal, state, or county government agency which removes any monument or has it removed.