Fossil corals: Sea Urchin Spines Fossils

What does James Parkinson (yes, the one who have discovered the Parkinson disease)  has in common with the Sea Urchin Spines Fossils ?

In fact, a lot !

He was a founder of the Geological Society of London and has written the Organic Remains of a former world  , that consists of a series of letters accompanied by hand colored engravings. 
One of these engravings show the fossils of sea urchins and sea urchins spines :

This engraving can be found also HERE .


A few days ago I have discovered two little (10mm) fossilized sea urchin spines and I am happy to show you the pictures. With and, without, microscope.