I would love to hear from any of the Surry co., NC descendants of Benjamin Pettit and Rebecca or Benjamin Pettit and Elizabeth about this Thomas Pettit. We would like to do a simple DNA test of targeted SNP's to see how closely this family may be related to the family of Thomas Pettit and Christian Mellows. Targeted SNPs can be done for about $18.

First Pettits in America Series #2 -Thomas Pettit, Rapp. Co, VA 1656
Thomas Pettit and Katherine his wife were in the Rappahannock River settlement in Virginia as early as 1656. They had one son, Thomas Pettit Jr and one daughter, Dorothy. It is likely that this Thomas is the ancestor of many of the Pettits in America today including those who trace their line back to Surry Co., NC.
Could this Katherine have been Katherine Morris, daughter of Maj. George Morris?
I Y-DNA matched on FTDNA with a Pettit descendant of George Pettit (b. 1775, Kentucky; m. Elizabeth Gillespie). He believes George was the son of Thomas Pettit (b. 1755; m. Rachel Monroe). Our results show we’re in a completely different haplogroup from the Pettit-Mellows line.
He’s currently waiting on his Big Y-700 results, but based on current data he’ll likely fall under I-FT384455 unless a new downstream branch is identified.
(Edit: I realize you may have been referring to Thomas Pettit (b. 1663; m. Rachel Wilson) or his father. His documented line does trace back to that earlier Pettit family.)
I’ve also matched a couple of other Pettits who descend from Benjamin Pettit and Elizabeth Sprinkle.
Hope this helps clarify things!
Well that's interesting. It sounds like you're close to getting your male line zeroed in. I have heard that the ancestors of Benjamin Pettit and Elizabeth Sprinkle may have spelled their name Pettis or Pettys. I am very curious what you find out. Please keep us updated!