The earliest verifiable record I have found for Thomas is a document he signed January 27, 1783. It was a petition to make a new state, Fayette, out of the area that is southwestern Pennsylvania and what was then northwestern Virginia. I have seen a copy of the document and what is supposed to be his signature. However, someone else may have signed for him if he wasn't able to read or wright. If memory serves, the Fayette petition came up as a result of the Whiskey War.
Geri Whitlatch