Tom, I can tell you that these were Presbyterian Blackburns in order to separate them from the Quaker Blackburns in the same region. Have you heard of an Ann Logan who married someone of your McNaughten line or one of the variations of the name (Knighten, etc.)? Could she be the widow of John Blackburn, brother of Benjamin Blackburn? One researcher thinks these Blackburns may be related to the Banjamin Blackburn line. This supports the legend that there were four, six, nine, depending on who tells it, brothers who came to America from Ireland. She refers to an Alexander Blackburn of PA who was possibly the father or uncle of the ones you name. Moses is a name in this line. It is also common in the Quaker branch. There was a Moses Blackburn who was a member of the Presbyterian church at Chambersburg. Perhaps it is the same man. M. Blackburn