Please help ID this

[up north]

When this broke open in my hand I thought it was a brachiopod fossil, but rinsing shows a lot more detail. The lower chunk is about 1/2'' thick. It is porous and looks like a bone. The top chunck (impression) is rock, and a lot more dense. Something about this reminds me of a cow tooth.
Please help me ID if you can. So far all I have found are marine fossils and would really like to record something new in my log. Thank you.

[allen]

not sure what it is, but its cool looking !!