Well, this is what has happened since I posted last week.
1. The Vigo County, IN Public Library is sending me a copy of my great grandparents' marriage certificate.My greatgrandparents are Elias Zane and Susannah Miller.
2. The Coles County, IL Clerk is sending me a copy of my grandfather's birth certificate.My grandfather is Arthur Chester Zane.
3. The Champaign County, IL Clerk is sending me copies of both my father's birth certificate and my grandparents' marriage certificate.My father is Justin Thayer Zane.
I've also found some possible discrepancies in past information.My grandfather had a brother, Francis Marion Zane.At first, I thought they were full brothers, because my current info has Elias marrying Susannah in 1874, 2 years before Francis' birth.But a 1880 Vigo County census shows a Miller household with a 29 year old Susan, and a 4 year old Francis M MILLER.Maybe Elias married her later than 1874; that would make Arthur and Francis half-brothers.
I'm told--and I'm getting a copy--of a 1900 Coles County census, which shows a Sue MORRISON, a 14 year old Arthur Zane, AND a 3 year old Everett Morrison.This makes Arthur and Everett half-brothers; it is also corroberated by the fact that my grandfather's death certificate lists his mother as Sue Morrison.