Welcome to Cointalk. Well the it appears the quarter has a piece of additional metal . Is it raised or incuse ? If it is depressed it is most likely post mint damage from something comming into contact with the coin. The spot on the dime appears to be incuse so it also could be post mint damage or... It could be a strike through of something done at the mint. Its hard to tell from the photos so Im sorry but I cant give a definitive answer but hopefully it will give you some directions to search. Maybe someone else will see it differently.
