“6 months have elapsed since the death of N.P. Dean” (Probate Court Minutes, 28 Feb 1870) ⇒ death on or before 28 Aug 1869
Probate court minute granting letters of administration states that six months had elapsed since the death of N.P. Dean as of 28 Feb 1870; this anchors death to on/before 28 Aug 1869.