Florida Fossil Fragment

[Craniate]

Newbie here. This is a little fossil I picked up on a beach in Southern Florida. When I first saw it on the ground I thought I had found a mammoth tooth fragment, but I'm guessing it's probably just some sort of shell. Any ideas?

Thanks in advance!

[miraspis]

Yes. Most probably it is part of some bivalve... I would say Scallop.

[Shellseeker]

Not scallop... oyster. Oyster shells seem to age/wear over long periods and end up in unusual shapes, A little breakage and enough wear makes then look like a fossil (which they might be).

[Craniate]

Thanks, Shellseeker and miraspis! It is heavy for its size and hard as a...well, rock, so I'm pretty sure it's a fossil.

Edited December 10, 2012 by Craniate

[BobWill]

Whether it's a scallop or an oyster depends on whether the lines are radial ribs or growth lines. Since they seem to converge at one end and are somewhat flattened I'd tend toward scallop.