Jody, I am an Alexander researcher and noted the name John Alexander with wife Susannah. Capt. John Alexander had a wife named Susannah. He was the son of John Alexander of Eredy, Donegal Ireland and known as John Junior. The book, Memorials of the Earl of Stirling and House of Alexander by Rev. Charles Rogers is all digitized on-line with Google books.Volume II has material on John of Eredy. John Junior's will of 1690 mentioned his wife Susannah and he was of Londonderry Ireland at that time.