The marine fossils on Manitoulin Island, Ontario, are associated with two geological periods, the Upper (Late) Ordovician (approx. 460.9 to 443.7 million years ago) and the Lower (Early) and Middle Silurian (443.7 to 422.9 million years ago). At this time, the island was near the equator and covered with shallow tropical seas. The fossils I’ve found, particularly at rocky Cunningham Bay and Janet Head, tend to be either Bryozoan colonies or Favosites (Tabulate Corals; that is, polygonal “honeycomb corals” or polygonal “wagon wheel” corals). Others I can't identify.
