She is Ellen in 1850 & 1860, but Nellie in 1870. However, she seems to be Martha H. (Remington) Fry in 1880, when she is married, has a daughter, and her father Stacy is living with them. For Stacy, the census says his relationship to the head of household is grandfather, but that is not likely, because Martha's husband "Frank" was born c1841, and Stacy is in the age range to be his father or father-in-law.