Newbie here, is this a fossil?

[Jonnerkop]

Hello all!

I found this on a beach of lake Michigan in Milwaukee, Wisconsin, USA. I was wondering/hoping it might be a fossil, I joined this form hoping someone could identify it. It was found on 7/20 washed up on a beach of small stones. thank you in advance for any response.

Edited August 3, 2019 by Jonnerkop
Adding information

[Jonnerkop]

 

[FranzBernhard]

Welcome to TFF from Austria, @Jonnerkop!

Yes, this is a fossil! The rings could be cross sections of corallites of a paleozoic auloporid colonial coral. The colony is firmly enclosed in a piece of limestone. But I am not 100% certain about the ID. Other more knowledgeable members from this area may help with exact ID.

In the meantime, try googling for: fossils lake michigan. The shore of lake Michigan is in some parts awash with fossils. Have fun!
Franz Bernhard

Edited August 3, 2019 by FranzBernhard

[Rockwood]

14 minutes ago, FranzBernhard said:

The rings could be cross sections of corallites of a paleozoic auloporid colonial coral.

Or not. I think it's a stretch.

They are probably small fossils though.

[TqB]

I believe they're mostly brachiopod shells.

[Scylla]

These are fossils, marine shells of some sort. You see some round cross sections, come crescent shapped ones and some lenticular ones. This is hard to ID exactly without knowing the formation it came from because you just don't see the diagnostic details. The age of most of the rock in that area makes it a good bet that brachiopods are in there.

[Mark Kmiecik]

Welcome to the forum from Illinois. 

 

Definitely a fossil. Not enough of any one animal there to ID, but they are all marine fossils of various shelled creatures. Keep looking. You'll find lots of corals and other fossils all in smooth rounded rocks that have been worn by the waves for a very long time.