May have been the Mary Ellis who married Ephraim Griffeth 10 Feb 1750 in Wareham, MA. Notice change in spelling of name Ellis as ELIS. Mary ELIS, daughter of Joel ELIS, born 7 March 1726, Plymouth, Rochester, MA., IGI pg. 12075.
Rochester Vital Records Vol. 1, page 124. Mary Elles, dau. Joel (Elis) and Mary, born 7Mar1726-7.