No Idea what we found

[belladora777]

Hello! We're vacationing the the Bahamas and found something we are unsure about. In fact, I'm not even sure it is a shell. I was just wondering if anyone would know what it is, as a search on the internet provided no results.

As it sits, it lacks all of those parts one would use to call it a shell.  It is mostly flat with a small curve inwards, raised ridges on the front, and a pearly underside.  Aside from the piece missing at the top (which appears to have attempted to heal over), the shape is intact as is.  At best guess, it looks like some form of scale or chitin.