What kind of rock is this??

Hi, my first guess would be 'shale' or limestone; essentially, compacted sand and mud that's a ka-zillion years old; it obviously had 'air bubbles' or 'vugs' in it at one time, or possibly, snails or sea worms--it's almost certianly from a sea floor originally, and has been smoothed-out by glacial transport, hence the holes; but ALSO...upon closer inspection, I see 'concentric' patterns here and there, so I'm thinking it's got very old remnants or 'impressions' of small, prehistoric creatures in it, which is always a bonus...! Sorry I couldn't nail it for you but it was cool enough I created an account for this great site and now I'm a member..! Hi everyone..!

I'd mostly agree with what's written there, though I would guess water to be the sculpting agent. Looks very fragile for glacial transport. I don't see anything to suggest it's man made. A cool looking piece.