Ok, what the heck? Seriously - obviously PMD, but what IS it? How did this happen? There is a large bump on each side of the coin, same spot. No dent - both sides are a raised bump. Additionally, there is a much smaller bump, reverse only, next to the arrows (Forgot to photograph that one), and that one, too, has no dent opposite it. Please look, and give me your opinions? What happened?
A related coin - it has a single, smaller bump on the reverse, but no mark or dent or anything on the obverse. Same problem?
Fire. The coins were in a fire. The fire heated a small bubble of gas inside the metal which expanded when the clad layers were heated.
