I'd say the lower one is the counterfeit note due to poor engraving, especially in the vignette, and the apparently reproduced signatures. But I don't know whether the bank even issued $10 notes in 1841 of same design as 1858 (or vice versa), nor do I know which are the correct signatures and how they look for real. Eric's note looks overall very much like a phony Bank of Cape Fear $10 note in my collection.

I think the top note is genuine. It looks to have better engraving on the vignettes. The signatures look good, matching genuine notes pictured elsewhere.

The bottom one is counterfeit. The engraving is poor, especially on the left end. The signatures look bad.

I think Eric used the Thompsons entry that mentions 10s payable at Lynchburg.

On the two notes of the Farmer's Bank of Virginia, the beat-up one is the counterfeit. It has considerable loss of detail in the vignettes, plus it is in position D on the sheet. President McFarland's signature has a descender that should have appeared at the top of that note, from when note C was signed. It is absent. It also lacks the second serial number applied by the bank at the upper right of the genuine note - a number that lacks a designated location, so the counterfeiter, not having a space there calling for a number, failed to enter one. I'm sure I could find more if I were not working from photographs.

Now I've scrolled down to the counterfeit detector. The 1841 $10, plate position D, made out to Radford, is cited as bad - which is the one I already identified from internal evidence. Note that neither note is signed by the cashier called for by the detector.