Since posting my query I have found that my Joseph Adair b. 1767 in Cecil Co. Maryland was the son of Samuel Adair and Hannah ___. Samuel died in 1773. We cannot prove past Samuel but family stories say that he was the forth son of Thomas Adair and the first son born in America. Still no proof. He is not the son of William Adair of New Castle, Delaware although the two families share similar names and lived within walking distance so undoubted knew each other. Samuel could be a nephew of William but again no proof.