Septarian Nodule

Septarians nodule were formed during the Cretaceous Period, around 50 to 70 million years ago. Periodic volcanic eruptions killed the smaller sea life which sank to the sea bed and started decomposing. The minerals in the shells and carcasses attracted sea floor sediments which accumulated around them and formed nodules or mud balls. When the ocean eventually receded, the mud balls dried out and began to shrink and crack into the beautiful patterns that you see in the septarian nodules.