Hello all, I was sorting through some penny jars today trying to fill a few holes in a folder when I came across this. I looked it up and it appears to be a Defective Die but I wanted some others to have a look at make sure it isn't post mint damage. Thanks, N.E.V.
Genuine mint error! This is a called a die break. The die cracked and then finally a piece of the die broke away and fell off the die. When it involves the edge of the coin like this one does it is called a Cud. since there was no die in that area the metal bulges up there and leaves that featureless lump. Also since there was no die there there was no pressure on the metal to force it into the recesses of the reverse die which is why the E CE is missing.