I found a pensioner listed in "Early History of Western PA" named James Buchanan. He was 85 years old at the time and living with William Logue and his wife, Catherine Buchanan Elder (b. 1810). Would James B. have been Mrs. Logue's uncle or her grandfather? Or some other relative? James Buchanan appears with the couple in the 1840 Census in Perry Township, Armstrong County, PA, listed as being between 80 and 89 years old, which would put his birthdate between 1751 and 1760.