Robert I. Boone, born August 1, 1837 in Kentucky. About 1875, he married Elizabeth Johnson, daughter of James Matthew Johnson and Charlotte Ballard. Robert died February 10, 1900 and is buried in the St Dominics Cemetery in Springfield, Kentucky. Elizabeth died January 17, 1933 and most likely is buried beside her husband but there is no marker for her there.
Christopher's father was Walter.
Charles Boone, born about 1725 in Prince George's County. He married Mary Boarman about 1745 in Maryland. Mary was the daughter of Thomas James Boarman and Jane Edelen. Charles and Mary died in Prince George's County, Mary by 1780 and Charles in 1783. Charles was the son of John II.
John Boone II, born 1678 in Calvert County, Maryland. He married Elizabeth Beaven about 1710 in Maryland. They both lived into their 80's and died in Prince George's County, Maryland.
John Boone was born December 27, 1645 in England and died before July, 1689 in Maryland. His wife's name was Grace. I have no last name, but I've found three different possibilities in other researchers online trees - Head, Meade or Bennett - with no sources for any of them. John and Grace may have married in Maryland. After John's death at about age 43, Grace remarried Robert Brooke. Grace died in 1725.