Does anyone know what I've found? Its an ammonite sphenodiscus but don't really know the value of such a find

Question

It measures 12 x 11 inches, it has 3 pieces that have broken off 1-larger and 2-smaller.

Answer 1

Wow!! I'm assuming it's fossilized! If it were alive you could write your own ticket.

As it is, these aren't unusual or particularly rare fossils. The Cretaceous period had a LOT of ocean.

And in less than perfect condition it's really hard to say. If I were you, i"d just keep it, put it on a mantle(if you have one) or any conspicuous place, and then when someone asks "What's that?" answer "Why, it's an ammonite sphenodiscus, of course, why do you ask."