Hello Herman,
I answered my own question! I know now that they are both buried at St.Joseph. They are mentioned in Elias's book. Kathleen Adams wrote it and at the time she said that she wasn't sure how Elias and Mary were related. Probably a cousin. She said that some of the Thurner children are buried on Louis Thoeny's lot at St.Stephen's Cemetery, but you probably already knew this!!
Hope to talk to you soon!!
Your Cousin,
Roxanne