Condor 101 is probably right. Something definately put a gouge or scratch in the die that struck this coin. I collect this type coins and have a few of the cent coins with die gouges going all the way thru Lincoln and a few cent coins with numerous die gouges going all the way thru the memorial building. I've been told this is caused by feeder finger damage to the coin dies. To me it looks like some mint worker just got carried away with coarse grinding material and never bothered to smooth the dies back out. these raised die gouges almost always are in straight lines like the one on the bison 5 cent coin.
