I am at a 99% certainty that this is just a weathered annularia, but there is a very small percentage of my thinking that it might be the cephalopod, Jeletzkya douglassae. I know that J. douglassae has 10 arms and this concretion has 9 branching (leaves / arms?). I collected this 1/2 concretion years ago at Pit 4 (Shadow Lakes- Braidwood Flora / Fauna) What do you think @fiddlehead, @RCFossils?