I been wondering for a while what could this possibly be. I thought a clash but nothing on the obverse side matches this mark which is incuse or could it be something else? It almost looks like part of the C from CENT.
It looks like the things you see on the top of the shield on the shield cents, and on some of the new nickels. I thinks someone said they were pre die break/crack, die depressions. Something like that. I could be wrong though.
the edges of the impression look raised like the metal was pushed up higher than the surface around it
Your right it is but what could of made a sharp impression like that leaving the surface of the incuse intact and un-damaged with its original finish?
this is a retained die chip . a small chip was getting ready to fall off the die . when this chip falls out then there will be a nice die chip in this area. this would be in the area where it could be called a hornet nest chip.
Rascal is closest to the truth. It's an area where the die sank in slightly. The sunken area is flanked by two thin die cracks.