From the Carboniferous,middle Pennsylvanian,Francis creek shale.
Collected from the Chowder flats, near Essex,northern Illinois,USA.
A Scyphozoan Jellyfish,often known as a hooded Medusa,the positive of the nodule is present.
The specimen displays the bell line from the underneath of the jelly fish ,so the top bulbous head is presumably at the top of the nodule as its all compacted
But the definition is often subtle and ambiguous.
Jellyfish are rarely fossilised, due to being made up of a Gelatinous substance instead of any hard parts,but the Mazon creek Laggerstatte is really very special.
The nodule measures 79mm x 71mm.