Ordovician Trilobite Geode

This Ordovician trilobite comes from the Atlas region of Morocco. It displays an interesting design in the original limestone matrix. 

This particular trilobite is from the Ordovician Period (approximately 485 to 443 million years ago), an era when trilobites were available in large quantities. They were marine arthropods and one of the most successful and universal groups of animals during the Paleozoic Era, thriving in oceans across what is now North America, Europe, and beyond.

I'm no trilobite expert, but these appear to be Calymene SP.