Mary Dickey's father, John, was born in Ireland circa 1702. He died in 1789 in York Districk, SC and is buried at the Bullock Creek Presbyterian Cemetery there. He came to Virginia in 1737 and settled in Albemarle County. He moved to SC in 1771. He received a land grant dated 10 Dec 1770 in Tyron County, NC, but when the land was surveyed it was in SC. He married Martha McNeely and was the father of Jane, John, George, Ebner, Robert, David, Susannah, Elenor, Mary, Martha, and William.
My files list Harriet Ivy as the granddaughter of Josiah Minter Hillhouse. Harriet also had two step-brothers, William and Leander Evans.
James Hillhouse (who married Mary Dickey) was a Revolutionary War Patriot. See page 447 "South Carolina Roster."