He's probably related to the Catts in my tree ;) but I haven't filled in too many of the branches there. I know that Philip Catt was the pioneer who moved his family from Virginia to the Northwest Territory, settling in Knox County near the White River. They became friendly with the Harness and Decker families of that same area who began marrying their children. I know that Philip's daughter Elizabeth (b. 1779, VA) married Luke Decker. Luke's family had also migrated west from Virginia and are now well known throughout the Midwest for their excellent melons grown in the sandy soil along the White and Wabash river valleys.
The Harness family may have also moved from VA to IN around the same time, but again, I have to research futher.