The Council may remove the Mayor for gross misconduct, malfeasance, misfeasance, and nonfeasance in or disqualification for office, or for the conviction, while in office, of a crime involving moral turpitude, or for violation of his oath of office, provided however, that such removal shall not take place without the concurrence of at least two thirds (2/3) vote of all the members elected to Council nor until the Mayor shall have been notified in writing of the charge against him at least ten (10) days in advance of any hearing upon such charge, and he or his counsel has been given an opportunity to be heard, present evidence, or examine any witness or witnesses in support of said charge.