............Cherrypicked from a roll last night. At first I thought it was glue or a cut or scratch in the coin. An acetone bath revealed this. It almost looks like this die was ready to shatter. The metal is raised and extends into the rim. Not sure about the exact definition, RIDB? shattered Die, bisecting rim to rim? split die?........but I'm pretty sure it's all there.
I've roll-searched many of these small dollar coins. I haven't seen anything quite like this on these modern dollars. I've checked several sites. error-ref, Cuds-on-Coins, etc.. Unless I'm missing it, I haven't found anything close.
Anyway, for your viewing pleasure and opinions....