I just did some research in Salt Lake City. Verified that my grandfather Samuel C. Addis was the younger brother of William Addis. 1880 census: Father William Addis day laborer 53born 1827 WifeAnnieAddis33 SonWilliam Addis16born 1864 Daughter Mary Addis14 SonSamuel Addis9born 1871 Boarder Nancy Hager33 Boarder Maggie Hager3 William's father was born in England,his mother in Ireland. family history library film1255/297-91129 Page 14B
Does this match your records? Do you have more info about the parents?