User:Abyssal/Portal:Carboniferous/DYK/3
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![Fossil of Agaricocrinus americanus.](http://upload.wikimedia.org/wikipedia/commons/thumb/1/16/Agaricocrinus_americanus_%28Roemer%29_%28Montgomery_County%2C_Indiana_-_USA%29_1.jpg/100px-Agaricocrinus_americanus_%28Roemer%29_%28Montgomery_County%2C_Indiana_-_USA%29_1.jpg)
- ... that siltstone deposits have allowed three-dimensional fossils of the extinct mushroom crinoid to be excavated from Indiana?
- ...that eighty years on, scientists are still debating whether the Palæozoic fossils known as Chitinozoans (SEM image pictured) represent plants, animals or eggs?
- ... that Arthropleuridea is an extinct class of myriapods which includes, at over 2 meters long, the largest terrestrial arthropods that ever lived?