Many thanks, Michalene...I found out what happened from the Crawford County Genealogical Society. Chauncey was married twice. His first wife was Amelia Webster, all right, but after their sons Ezekiel & Penn were born, Amelia died in 1874. Chauncey married again after that Ella Hubbard), and it is his second wife that appears in the 1900 and 1910 census data. Simple explanation, but I hadn't even thought of it. Glad to have confirmation of the first part of the story from another source!