The will of James Sparks names sons Daniel, John, and Henson. This is one of the shakier links since I don't have proof that these are the same Daniel and John Sparks named in the land records with Samuel Sparks. The time period and location in Queen Anne's County seem to fit.
The other shaky link is the one from James to William Sparks, Jr. The Sparks Quarterly Issue 124 has an explanation of why James Sparks is the probable son of William Sparks, Jr. According to the Sparks Quarterly, William Sparks had four sons: William Jr., George, John, and Joseph. Wills and estate settlements of John, George, and Joseph name their children, but none of them are believed to be the James that married Elizabeth Burkhurst.
Sources for the first four levels in the tree are the Sparks Quarterly and the Sparks Family Tree.