Cal. Civ. Code § [2120.]

Section Twenty-one Hundred and Twenty. If, for any reason, a carrier does not deliver freight to the consignee or his agent personally, he must give notice to the consignee of its arrival, and keep the same in safety, upon his responsibility as a warehouseman, until the consignee has had a reasonable time to remove it. If the place of residence or business of the consignee be unknown to the carrier, he may give the notice by letter dropped in the nearest Post Office.