Ahhh...that makes perfect sense. About Mary becoming a citizen after her marriage.
Rose Marie, my Grandma, was married in Butler County in 1939 to Richard Wilson. She was born 06 Aug 1919. Now looking at her marriage certificate, which I have right in front of me, it does state that Mary was born in Pittsburgh! Why I never saw this before...Okay. I'll look into her being born in Pittsburgh now.
When it comes to the 1930 census...I found that the house they were living in at that time was passed up. The 3 houses on the block were never taken during that census. That is why we can't find them on that particular census. I would love to see the 1900 & 1910 census you are speaking of for Mary Margaret. Is the spelling for her maiden name Tetzlaw, Tetzlow, Tetslow or Tetslaw? I have seen it all ways now.