Cal. Rev. & Tax. Code § 256.7

(a) Notwithstanding Sections 254, 256.5, and 256.6, an affidavit claiming the cemetery exemption, as provided for in subdivision (g) of Section 3 of Article XIII of the California Constitution and Section 204, is not required to be filed in order to receive the exemption for any cemetery that exists, or is discovered to exist, in the unincorporated area of a county for which the assessor is unable to identify the legal cemetery authority, as defined in Section 7018 of the Health and Safety Code, that may by law claim the exemption for that cemetery, if both of the following apply:
1. (1) The cemetery was used by residents of the state prior to the year 1900.
2. (2) The cemetery is no longer used for current or future interments.
(b) Any tax, penalty, or interest imposed upon a cemetery subject to this section shall be canceled pursuant to Article 1 (commencing with Section 4985) of Chapter 4 of Part 9, as if it had been levied or charged erroneously.