A.

The designations, locations and boundaries of such districts are set forth on the sectional district maps showing the zoning plan provided that all the unincorporated territory of the County of Trinity not included or indicted on the sectional district maps is hereby designated as in the "U" district.

B.

The aforesaid districts and certain combinations are hereby established insofar as the designation, locations and boundaries thereof are set forth and indicated in Chapter 17.04, and other sections of this title which describe certain of said districts; Chapter 17.08, which consists of index map to various sectional district maps, and Sections 17.09, 17.09.1, 17.09.2 and other sections of this title, each of which other section is designated by the number 17.09, followed by a period and numeral or letter, and which section consists of a sectional district map which shows the designation, locations, and boundaries of certain said districts. Said maps and all notations, reference data, and other information shown thereon are hereby made a part of this title.

C.

Where uncertainty exists as to the boundaries of any of the aforesaid districts as described as aforesaid or as shown on said sectional maps, the planning commission, upon written application, or upon its own motion, shall determine the location of such boundaries.