On the coming into operation of the said Part III the jurisdiction of a juvenile court in relation to the care and protection of children shall cease, and any case of a child under the age of sixteen years which was before the court under that jurisdiction immediately before the said commencement shall stand referred to the F1Principal Reporter of the local authority in whose area the child is ordinarily resident, or, where his ordinary residence is not known or is furth of Scotland, to the F1Principal Reporter of the local authority in whose area the circumstances arose which brought his case before the court.