The several districts into which the City of Mill Valley is divided are designated as follows:

Locations, boundaries, designations and classifications of the districts hereinabove established are delineated upon the map entitled, "Zoning Map City of Mill Valley," dated April 3, 1975, and as amended from time to time, which map is on file with the Planning Department and is made part of this title.

Where uncertainty exists as to minor discrepancies in boundaries of any zoning district as they appear on the zoning map, the Planning Commission, upon its own initiative or upon written application, shall determine the location of such boundaries.

Areas which shall hereafter be annexed to the City of Mill Valley shall, immediately upon annexation, be automatically classified as U Districts until their proper classifications are determined pursuant to the regular procedures for rezoning as required by law. The Planning Commission shall initiate rezoning procedures to place the newly annexed area into a precise zoning district. Such procedures for proper classification shall be initiated within three months following the date of annexation.