It's my pleasure to help in any way I can. Here is a complete transcription of this note, which now resides with the Goff Collection at the WV Archives in Charleston, WV:
"Mr. Jas Goff Dr To the
Sherif thomas holder
2=16=4 for Clarks notes"
"Jas H Jenkins
in the year of our
Not much to go on here. When I made the original post, I only had access to side one and did not know about the 1791 date. James Goff lived in Loudoun County until about 1774, which doesn't seem relevant to Thomas Holder in regards to this document.
Good luck in your search. Thanks.