I know that many Trees show Allen Dunn Hollenbaugh's wife's name as Margaret Cannon, but I have a Death Certificate for one of the children (Seth Hofius Hollenbaugh) that lists his mother's maiden name as Margaret Maxwell. I'm not sure where the name Cannon came from but there was no supporting documentation for that name.
The Death Certificate also shows that the name Hollenbaugh was changed by Seth to Holinbaugh. James Elmer changed it to Hollibaugh. I attached a copy of the Death Certificate for your documentation.