The Copper Harbor Conglomerate is a

geologic formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...

Michigan Michigan () is a U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, upper Midwestern United States. With a population of nearly 10.12 million and an area of nearly , Michigan is the List of U.S. states and ...

. It is part of the larger

Oronto Group The Oronto Group is a thick group of arkose sandstone and shale located beneath the Bayfield Group in northern Wisconsin,Bulletin, p. 48. along the northwestern side of the Keweenaw Peninsula and southern Isle Royale, and believed to extend into ...

and its formation dates to the

Stenian The Stenian Period (, from grc, στενός, stenós, meaning "narrow") is the final geologic period in the Mesoproterozoic Era and lasted from Mya to Mya (million years ago). Instead of being based on stratigraphy, these dates are defined c ...

period of the

Proterozoic The Proterozoic () is a geological eon spanning the time interval from 2500 to 538.8million years ago. It is the most recent part of the Precambrian "supereon". It is also the longest eon of the Earth's geologic time scale, and it is subdivided ...

References

* Stratigraphy of Michigan {{Michigan-geologic-formation-stub