Still another clear, accurate and very detailed genealogy can be found in the book entitled: History of Nathaniel Evans of Cat Fish Creek and his descendants, Chapter IV p. 77 by James Daniel Evans (Williamsburg, VA, 1905). The book is available as a resource at Ancestry.com and at the following location: https://archive.org/details/historyofnathani00lcevan/page/77/mode/2...
In this work by James Evans, John Knox’s appearance and that of John Witherspoon the founder is only incidental to the main thrust of the genealogical line that is being presented. John Knox appears as the 9th generation descendant and John Witherspoon as the 13th. Significantly this genealogy is more focused on following the line of Dr. Witherspoon’s sister Ann Witherspoon who married James French, a Rector of the High School of Edinburgh. This genealogy has deeper aspirations in showing the connection to King Robert the Bruce (1274-1329) and does not have an axe to grind regarding Dr. Witherspoon’s descent from John Knox but does in fact state and prove this