congrats.
It looks like it may well be a unique brown old mill freak.
It looks as though the brown color appears on very freakish places on the card perhaps
due to the printing process being affected by the shift in the sun's magnetic fields--- which should have occurred during the 1909-1911 span of time.
I do wonder why other old mills were not affected in similar ways---unless they
are being hoarded by a collector or collectors.
Still, quite a coup, waz.
all the best,
barry
for purposes of clarity