I just found this list on Rootsweb: List of Lot Owners in Hillside Cemetery up to April 1, 1890 at
http://www.rootsweb.ancestry.com/~nywestch/cemetery/hillside.... Note that Dr. A T Cuzner, Mary's oldest son, owns a plot in this cemetery in Peekskill. Dr. A T Cuzner at that time lived in Gilmore, FL and is burried there, so this grave must have been for someone else. William Thomas Cuzner, s/o George John Cuzner, Mary's youngest son, was born in Peekskill, NY in 1873. I haven't found an actual grave listing, but this seems like an interesting lead.
If anyone has actual grave listings for this cemetery, I'd appreciate the info.
Steve