I will need to look as I've had a lot of personal troubles that have taken me away form research as of late... BUT, off-hand I do not recall a Robert you mention as George Sr'sfather.
I have (in short):
William Elliot Sr. was born July 12, 1699 in Amtrin, Ulster Ireland (other sources say Scotland), and died 1795 in Rockbridge County, Virginia. He married Margaret Graham bet. 1713 - 1747. She was born Bet. 1680 - 1709, and died 1773.
more notes for William Elliott, Sr.: William Elliott, Sr. was born 12 July 1699 (probably in Scotland or Ireland) and emigrated to the new world about 1730. After spending about ten years in the Cumberland Valley of Pennsylvania, he moved to the Calf Pasture (what is present day Rockbridge County, Virginia) along with William Gay and James Stevenson. William Elliott resided in Beverly Manor until his death in 1795. He was a prosperous and prominent man, being a cattle farmer by trade - there are many listings of him selling cattle with his sons in extant newspapers of the period. Unfortunately, when he died he left his entire estate to his son James, who had cared for him in his old age, and as a result it will probably be impossible to know who all of his children were.
Marriage Notes for William Elliott and Margaret Graham: William and his wife Margaret attended the Tinkling Springs Church where the birth of his youngest son Robert is listed - 7 July 1743.
Generation No 1. William Elliott and Margaret: i.Andrew2 Elliott, born Abt. 1717. ii.James Elliott, Sr., born WFT Est. 1720-1749; died 1799 in Rockbridge County, Virginia. iii.William Elliott, Jr., born 1721; died 1771. iv.Richard Elliott, born Abt. 1722; died Bet. 1726 - 1828. v.Archibald Elliott, born 1726. vi.Robert Elliott, Sr., born July 07, 1743 in Augusta County, Virginia; died May 1802 in Woodford County, Kentucky. vii.GERORE ELLIOTT, Sr., died Abt. 1804 in Madison County, Georgia <<< ECS HAS THIS.... lots more info on this line>>
Generation No 2. GEORGE ELLIOTT SR George Elliott, Sr. (William1)died Abt. 1804 in Madison County, Georgia. He married Mary Henny.
Notes for George Elliott, Sr.: With others from the community, he set out from Cumberland County, Pennsylvania for Georgia in 1785, but hearing in Virginia that the Indians were hostile in Georgia, they stopped one year in Rockbridge County, Virginia, and then in the fall of 1786, continued their journey . They settled in the neighborhood of New Hope in what is now Madison County, Georgia. Most of the sons of George Elliot, Sr. were married at the time. They were mechanics and blacksmiths. It is said that the Elliots helped make the chains which were stretched across the Delaware River to impede the British fleet at Red-Bank and Mud Island in 1777. They also made the nails for the construction of the first meeting house of the New Hope Presbyterian Church.
Children of George Elliott and Mary Henny are: i.Alexander3 Elliott, ii.George Elliott, Jr., iii.James Elliott, iv.Margaret Clay Elliott, v.Robert Elliott, vi.William Elliott,