Cal. Bus. & Prof. Code § 8760
Every licensed land surveyor or registered civil engineer may administer and certify oaths:
(c) When the importance of the survey makes it desirable, to administer an oath to his assistants for the faithful performance of their duty.
A record of oaths shall be preserved as part of the field notes of the survey and a memorandum of them shall be made on the record of survey filed under this article.