Found in a river bed. Help identify?

[lowd]

Hi guys I found this in a creek bed. It's fossilized and rather heavy for its size. Any clue as to what it may be?

 

[GatorBoy]

Looks like it used to be a small box turtle

 

[kenstein]

The interlocking seams resemble those of a Baculite, but the shape doesn't. If you have a Natural History museum nearby, they can help. Let us know what you find out. Interesting.

 

[bakergeol]

Coiled cephalopod- Big one.

 

[Ninjafossils]

As you saw on the other post it is in fact an ammonite