Diane, Your Mark Jr. who md. Mary Warren I am showing as the son of Odian Castleberry. Odian is a brother of Mark Sr. Please remember back then Jr. didn't necessarily mean son of, it just meant younger than two members of the same family with the same name. Here is info I show on Odian:
The will of Odean Castleberry made 31 Mar 1841 is on page 4 of the Ledger covering May Term 1844, for Forsyth Co., GA
Executors: William Castleberry, B. W. Castleberry, Timothy Castleberry, Henry Tedder, David Putman
Heirs: wife Margaret in her widowhood at her death or remarriage divided among my children to their satisfaction if not equally divided.
Children: Mark Castleberry
David Castleberry
Sarah Tedder
Liry Putman
John Castleberry
Odum Castleberry
William Castleberry
Benjamin W. Castleberry
Timothy Castleberry
Witnesses:
William Heath, David Tallent Jr., David Tallent, Sr.
These records are in the Probate Court, Forsyth County Courthouse, Cumming GA 30040.