Kolts (Koltz) family in Burnside, Lapeer County

Looking for info. on Nancy Jane Beals (a Maine native) who married Mathew Kolts (or Koltz) from Germany (Prussia) and had several children while residing in Sanilac county and then Lapeer county. Looking for info. on Nancy's death specifics, as I suspect she must have died btwn 1875 and 1880. I have much information on this couple, but really desire to find a record of Nancy's death. A bonus would be to locate where she is buried; I haven't been successful in either search. Thank you.