California Code, Government Code - GOV § 9510

When the Governor approves a bill, he shall affix his name thereto, with the date of signing, and deposit it in the Office of the Secretary of State, where it becomes the official record. Upon the receipt of any such bill, the Secretary of State shall give it a number, to be known as the chapter number. He shall number each bill in the order in which it is received by him, and the order of numbering shall be presumed to be the order in which the bills were approved by the Governor.