The notice of filing or other submission of the proposal shall contain the matters specified by the law under which the proposal is made. In lieu thereof it shall be sufficient if the notice of filing or other submission of the proposal shall contain the following:
(a) The nature of the proposal.
(b) A general description or map of the territory included in the proposal.
(c) The time and place of the first public hearing on the proposal if a public hearing is required by other provisions of law to be held upon the proposal, or the time and place upon which the supervising authority will take initial action upon the proposal.