can someone ID. this slab

[GatorBoy]

I've had this for some time now.
Just kept pushing it aside shrugging my shoulders.
Mabey giant tortoise shell?..but no curvature.

 

[GatorBoy]

 

[Perico]

Thick like giant tortoise. Not sure though.

 

[GatorBoy]

It must be.

 

[old digger]

Maybe a lower jaw section?

 

[GatorBoy]

The part about the Tortoise shell idea that doesn't fit for me..besides lack of any curvature is that neither side looks like shell exterior.
I found everything from horse to mastodon sloth and tortoise here.. jaw section ..Hmmm.. Mabey.
The lattice work on the interior is long like I've seen in jaw sections.
.

 

[GatorBoy]

Could definitely be a piece of one.