Upon the filing of such petition in the office of the county clerk, the county clerk shall determine and certify that such petition has been signed by at least sixty percent of the freeholders whose names appear on the current tax schedules in the office of the county assessor and who appear to reside within the suggested boundaries of the proposed district. He shall thereafter designate a time and place for said petition to be heard by the county board. Notice of such hearing shall be given by publication two weeks in a newspaper of general circulation in the county, the last publication appearing at least seven days prior to said hearing; said notice shall be addressed to "all persons residing in or having any interest in real or personal property located within the following boundaries" and shall include a statement of the proposed boundaries as set forth in the petition; PROVIDED, that if the proposed district shall be situated within two or more counties, the county clerk of the county wherein the largest number of petitioners shall have signed, shall confer with the clerk or clerks of the other county or counties concerned and shall obtain a certificate as to the adequacy of the petitions pertaining to said county or counties, and thereafter he shall designate a time and place for a hearing before a joint meeting of the county boards of all counties in which the proposed district is to be situated and shall give notice thereof by publication in the manner hereinbefore provided. At the time and place so fixed, the county board or boards shall meet, and all persons residing in or owning taxable property within, the proposed district shall have an opportunity to be heard respecting the formation of such district or the location of the boundaries thereof. Thereupon the county board or boards shall determine whether the proposed district is suited to the general fire protection policy of the county, or each of such counties, as a whole, determine the boundaries of the proposed district, whether as suggested in the petition or otherwise, and make a written order of such determination which shall describe the boundaries of the district and be filed in the office of the county clerk or clerks of each county in which such district is situated.