If what u said it all real, u r pretty productive. Is there any other reason you did not mention? I am very shocked by the decision from your chair; usually a new fauculty will be given 5-6 years to prove him/herself. I guess there is something else you do not want to mention or you do not even know.
Talk with a lawyer and find all possible flaws from the chair. I know they do not like to fight in the court.