Basically you have four grand parents similar to mine below. The children of my grand parents are my Parents and Uncles and Aunts. The Surnames to the right are the names associated with that branch of ancestors.

Pulliam
(Grandpa)
Mom Side		Bates, Davis, Ficklin, Galyean, Holladay, Newby
Priddy, Stuart, Toliver, Walker, Wilson, Underwood
Pease
(Grandma)
Mom Side		Clark, Fischer, Goodman, Houser, Seiferlein
White
(Grandpa)
Dad Side		Adair, Alexander, Barker, Duncan, Graighead, Hulin
Hunt, Leach, Potts, Pounds, Stewart, Vickers, Witherspoon
McDougal
(Grandma)
Dad Side		Dudley, Jones, Howard, Lankford, Norwood,
Reynolds, Spears, White
The surnames list is a partial list
Great Grand Parents (8)2nd Great Grand Parents (16)3rd Great Grand Parents (32)4th Great Grand Parents (64)
Pulliam/
Wilson		Pulliam/
Priddy

Wilson/
Underwood
Pulliam/
Ficklin

Priddy/
Walker

Wilson/
Galyean

Underwood/
Osborne		Benjamin Pulliam/Lucy Stuart

Joseph Ficklin/Ester Newby

John Priddy/ Nancy Whitlock

Still working on others.
Pease/
Houser		Pease/
Goodman

Houser/
Seiferlein
Pease/
Clark

Goodman/
Mason

Houser/
Fischer

Seiferlein/
Unknown		Still working on these folks
White/
Barker		White/
Alexander

Barker/
Stewart		White/
Vickers

Alexander/
Duncan

Barker/
Pounds

Stewart/
Leach		Francis Alexander/
Jane Adair

William Leach/
Milly Hulin

Still working on others
McDougal/
Reynolds		McDougal/
Spears

Reynolds/
Jones		McDougal/
Norwood

Spears/
White

Reynolds/
Spears

Jones/
Howard		Samuel Spears
1760 VA –
1837 TN
Sallie Ann Dudley
1763-1849

Still working on the others

Keep in mind that when one of your grand parents has more that one spouse and has other children, then the half cousins become factors. Not listed in the above chart is the 5th and 6th great grand parents that I know of, but still working on finding citation records.