Thanks so much for taking the time, Galium. I have been looking at that and as well as the will of Eustace's father (another Eustace). Somehow the whole line goes back to Tetsworth, Oxfordshire but I am missing a few significant pieces to the puzzle.
So I suspect Eustace Petty 1660-1675 is the son of Eustace Petty d. 1682 and Elizabeth (maiden name unknown) d. 1685
The Eustace you kindly found was married to Mary Rice b.1663-
?
Here is a list of known Siblings for Eustace 1660-1675
Joyce Petty m. Thomas Plater
Judith Petty m. Alexander Travell
Jane Petty 1648-1717 m. Edmund Mason and later John Parran 1638-1725
Alexander Petty of Hethe 1653-1725 m. Mildred (maiden name unknown)
Nathaniel Petty
Alexander Petty is well documented but I have very little on Nathaniel other than another litigation reference involving himself and sister, Joyce against their brother-in-law, Alexander Travell.
Elizabeth Mason has two brothers-in-law cited in John Mason's will. Neither of whom is an Edmund. I obtained Edmund's name via Eustace Petty's d. 1862 Will. Nonetheless, Edmund may be a deceased sibling to them.
I don't think Elizabeth is Eustace 1660-1735 2nd wife because she outlives him by a year but is not mentioned in the will.
I have no death date for his 1st wife, Mary Rice b. 1663
Rachel (thanks again)