At the time of the Civil War, there appear to have been men in two Virginia counties by this name. They are Greenbrier and Monroe. One of these was a commissioned officer during the war, Lieutenant David Jameson, Co. "D", 14th Virginia Cavalry.
I cannot verify the existence of a 'Colonel' David Jameson, nor can I confirm residence in Culpeper Co. What is your source for this information?
You may wish to ask this question on the Virginia in the Civil War message board.