Judy, Our Ephraim McLean DAR Chapter in Waynesboro has a member, Eva Wise, who is a descendant of Isaac Horton. Her address is 500 Sunny Acres Lane, Waynesboro, TN 38485, 931-722-9279. Our Chapter marked his grave on June 1, 1986. Maybe Mrs. Eva can help you. Thanks, Betty Rains Anderson Waynesboro, TN