CA Gov't Code Section 27320

When any instrument authorized by law to be recorded is deposited in the recorder’s office for record, the recorder shall endorse upon it in the order in which it is deposited, the year, month, day, hour, and minute of its reception, and the amount of fees for recording. The recorder shall record it without delay, together with the acknowledgements, proofs, certificates, and prior recording data written upon or annexed to it, with the plats, surveys, schedules, and other papers thereto annexed, and shall note on the record its identification number. Efforts shall be made to assign identification numbers sequentially, but an assignment of a nonsequential number may be made if not in violation of express recording instructions regarding a group of concurrently recorded instruments and if, in the discretion of the county recorder, such assignment best serves the interest of expeditious recording.