Hemicidaris luciensis Plate

Hemicidaris luciensis (D'Orbigny 1850)
From the Jurassic,Upper Bathonian.
Collected from Luc sur Mer,Calvados,France.
An absolutely stunning thick plate of sea urchins and spines
This would be described as a mortality plate,There are at least six complete echinoids on the front and one big one on the reverse, as well as loads of spines,there is no one direction to the orientation of the spines suggesting there was little or no current, making this a very tranquil environment.
The entire plate measures 116mm x 72mm.