When I first saw this coin, I thought someone had taken a knife to it, but after looking closer, I think it is a massive planchet flaw. The reverse does not show any damage. I am no expert and am wondering what others think.
Yup! That's a lamination error alright. And although they don't command tremendous premiums unless the peel is extremely large, they are always neat to find and are definitely worth keepin'. -Brian