The Munising Group or Formation is a 1,700 feet (520 m) thick, white to light grey[1] Cambrian sedimentary unit that crops out in Michigan and (to a lesser extent) Ontario.

[3] Its uppermost strata may be Early Ordovician in age, and contain conodonts, trilobites and phosphatic moulds of brachiopods, ostrocoderm fish and gastropods.

It is named for Davis Creek located in St. Francois County, Missouri by Buehler (1907, p. 231).

It is stratigraphically equivalent to the Davis Formation to the east and south of an arbitrary cutoff line in northwestern Indiana.

[11] The Galesville Sandstone is a geologic unit found in Northwestern Indiana and Wisconsin.

In southern and western Indiana it is a named member of the Davis Formation this continues into Illinois.

The Eau Claire contains Trilobite fossils that date back to the Early to Mid Dresbachian Age (501-497 Ma).