The council shall hold a regular meeting at least once each month in the city at a time and at a place which it designates. It shall adopt rules for the government of its members and proceedings. The mayor upon his own motion may, or at the request of three members of the council shall, by giving notice thereof to all members of the council then in the city, call a special meeting of the council for a time not earlier than twenty-four (24), nor later than forty-eight (48) hours after the notice is given. Special meetings of the council may also be held at any time by the common consent of all members of the council. Twenty-four (24) hours prior to a special meeting a public notice shall be posted in three places in Depoe Bay, including the Post Office, and the two nearest radio stations shall be notified. Mention must be made of the reason for the special meeting, and only such designated business shall be transacted.