I told ya before, Miss Betty, sometimes you have to sideways finesse. Spellings I found on various documents were FULKS, FULKE, FOLKE, and FOLKS , sometimes in the same family it seems. And don't neglect land records ! Sometimes, if the oldest would be inheriting the big farm, Pops would buy the other kids smaller pieces of land adjacent or nearby when they got married.
And look for Clark's will. Frequently uncles and or brothers were executors, administrators, bondsmen for surety and witnesses. Further clues for the daddy hunt.
There are several citations for a RICHARD " THE IMMIGRANT" FOULKE whose grandsons moved to Georgia. Surname spelling among his progeny varied.