The planning commission shall determine whether the tentative map is in conformity with the provisions of law and of this chapter, and upon that basis, within thirty days after the filing of the tentative map, unless the subdivider has consented to an extension of time, approve, conditionally approve, or disapprove the same, and shall report such action direct to the subdivider and shall also transmit to the city engineer a copy of the tentative map, and a memorandum setting forth the action of the commission thereon. (Ord. 89 § 3.5(a), 1955).