What is this Fossil from Lake Erie?

[Ellen197311]

Any clue what this is? It's about the size of a quarter, but thicker. It was found on a Lake Erie beach in OH (30 minutes west of Cleveland, OH). Most fossils from this area are from Dovinian period. It looks like a bunch of shells stuck in chocolate. Are these crinoids?

 

 

[Raggedy Man]

This is a piece of a hash plate thats been tumbled and worn by water. There could be crinoid stem fragments, corals, bryozoan and what looks like brachiopod fragments. I find these all the time while metal detecting the local beaches. Determining the age of this would be difficult unless an index fossil( a fossil only found in one geological time period ), is present. The surrounding bedrock of the greatlakes spans from the ordovician, silurian and devonian.