Jonathan Fitzallan Gragg is my 4th great grand uncle and Henry Gragg is my 5th great grandfather. I have Henry's parents listed as Edward Gragg and Mary Holmes.

This is the information I have on Edward:

Edward Gragg
Birth abt 1729 in Scotland or County Antrim, Ireland or Fairfield County, South Carolina, USA (conflicting info on ancestry.com)
Death abt 1782 in Fairfield County, South Carolina, USA

No info provided on his marriage to Mary, just her name from another Gragg family tree on ancestry.com)