Thanks! In the 1860 Census I could find a Thomas Thurmon who was 50 residing in Carroll County and another who was 16 residing in Taney County. The older Thomas had a son named Congrave who was 25 at the time. Possibly his name was shortened to become the G. Thurmon listed on the register. The members of Company C that I've located so far are from south/central Missouri counties - which is why I first assumed they were in the Sixth Division. Just puzzled.