Cal. Health & Safety Code § 7905

With the approval of the governing body of the city or city and county in which the cemetery lands are situated, sufficient lands may be reserved from any cemetery lands from which the human remains have been removed to erect a mausoleum or columbarium for the reinterment of disinterred remains, to provide sufficient grounds around it, and to preserve such historical vaults or monuments as the cemetery authority may determine to be proper or necessary.