Posted 06/09/2018 9:27 pm
If youre talking about the discolored areas inside of the memorial, I'm guessing it's the remnants of a die clash. The 88's in particular seem to have been susceptible to that a lot. That's why you tend to find a lot of gouges and stuff from the dies being polished a ton to remove them. The big giveaway is that semicircle in the third bay from the left of the memorial. If you look at the obverse, it corresponds with the back of Lincoln's neck.
