Mazon Creek circular nodule ID

[AnomalyShrimp]

Hello! A couple weeks ago my family and I drove to Mazon Creek and found our first nodules. I was keeping my eye out for the tell-tale round layered shale, and picking up already split ones too. I also saw a similar thread posted recently, just want to confirm if these are indeed duds or not!

Most of the finds are about 3cm

#1, The most intriguing one to me

#2

#3, all of them together to show frequency and variety of circle pattern

Thank you very much for reading!

[Rob Russell]

Hey there. It looks like a few of your already open nodules may be jellyfish fossils. Soaking them in vinegar for a few hours, and then gently scrubbing off the “white stuff” will reveal what’s under there.  The ones you’ve shown that opened; and aren’t covered with the white stuff, don’t appear to have fossils in them. 

[AnomalyShrimp]

Thank you very much for the tip, @Rob Russell!

Here's how a lot of the finds cleaned up:
#1

#2

#3

They may all still be duds, but thank you for the second opinion! Even the idea of the possibility of jellyfish fossils is amazing to me

[Mark Kmiecik]

Be careful how long you soak them in vinegar or any other acid. Acids also attack the iron siderite matrix, effectively erasing the fossil.