Gov. Code, § 25209

If real property is conveyed by a county and it is subsequently determined and mutually agreed by the board of supervisors and the person to whom the property was conveyed that an error was made in the description of the property conveyed, so that less property is included in the description than was intended by the parties, the board may by resolution recite the facts of such error and approve such determination and agreement; thereafter the board may execute or cause to be executed a corrective deed without conforming to the requirements of law, if any, for the sale of real property by counties and without commencing a judicial action to reform the deed.

A similar procedure may be followed with respect to property conveyed to a county, where the error results in more property being conveyed than was intended. In either case the resolution of the board shall be conclusive as to the facts recited therein as to good faith purchasers or encumbrancers for value.

This section shall not apply to a conveyance by or to a county if the error is in the published description required by law or charter, nor shall this section require notice of such sale or purchase to be published if not otherwise required by law.