I found two obituaries for you. Unfortunately neither give the maiden name for Mary ... however her obituary does mention her growing up in the Town of Clarence and Lyons. Hopefully this information along with the maiden name possibility given to you by BurgessDonnelly will be helpful to you in your search. You may want to contact the church that is named, they may have all the information you are looking for.
I found these obituaries on this website, there are other articles about the family you may be interested in.http://fultonhistory.com/Fulton.html