I have no idea who this duncan Blair is, but thought it might help you.
Canada New Brunswick provincial archives
Rs10 land petition : original sereies 1783-1918

name: Blair duncan
year 1787
county York
microfilm F1032
see petition of Blair, duncan

name: Blair duncan
year 1788
county York
microfilm F1034

name Blair duncan
year 1791
county York
microfilm F1037
see petition of Blaicher, jacob david

name Blair duncan
year 1792
county York
microfilm F1038
see petition of Marygold,thomas

name Blair duncan
year 1800
county York
microfilm F1041