Middle Devonian, approximately 380 million years old, Columbus limestone, Ingersoll, Ontario.
The Columbus limestone is rich in fossils such as the one illustrated here: a Favosites coral colony, common called "honeycomb coral".
Rugose coral are cone shaped, with a wrinkled outer surface. Rugose means wrinkled. This one is broken down the middle and shows the radiating pattern of the septae looking like bicycle spokes. both of these types of coral are now extinct.