In the 1870 US Census for Union, Tioga County, Pennsylvania the family of Erastus Newell was enumerated as follows:
Dwelling #98; Family #101
Newell, Erastus; 27; M; W; Farm laborer; b. Pennsylvania; Male citizen of US of 21 years of age and upwards
Newell, Thena; 26; F; W; Keeping house; b. Pennsylvania
The parents of Erastus, Josiah and Phebe, were living two houses away, in Dwelling #100.
By 1880, Erastus was married to Sarah unknown, and they were living in the same place with his son Ralph M. Newell, age 10. We can speculate that Thena died in childbirth and Erastus later remarried.