Have you read Pippinger's book on this John Alexander? It is rather interesting and if this is your line, you should be able to get this through interlibrary loan. He does not believe that this John was the son of Sir William. He states material that says that that John Alexander married to Agnes Graham of Dartmore died soon after being released from debtor's prison in Scotland. My line is the Somerset Co. MD line, but there may be some connection with the Virginia line.