Rare chain coral

Rare Chain Coral from Lake Huron - Estimated age at 416-460 million years old It existed from the Late Ordovician Period to the end of the Silurian Period (461 to 416 million years ago). It is called "chain coral" due to its chain-like structure formed by individual corallites (tubular chambers) connected side by side. Halysites was a colonial marine invertebrate that attached to the sea floor, and some species were important reef builders. Fossils are commonly found in Silurian-age rocks, including those in the Great Lakes region, such as Lake Michigan & Lake Huron. Individual corallites are typically 1–3 millimeters wide and have circular to oval cross-sections.