Early Ordovician (Arenigian)

Upper Fezouata Formation

Zagora, Draa Valley, Morocco

11mm sponge on 52mm slab with 7mm hyolithid

Sponge,

Here is an unusual association piece with a sponge and a hyolithid.

Hyolithids are shelled invertebrates of uncertain classification though the latest research places them perhaps related to brachiopods.  They reached their greatest abundance and diversity during the Cambrian but suffered greatly during the mass extinction at the end of that period.  The group went into decline but still managed to survive into the Permian before becoming extinct.