The Freda Sandstone 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 peninsular U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, Upper Midwestern United States. It shares water and land boundaries with Minnesota to the northwest, Wisconsin to the west, ...

. It dates back to the

Proterozoic The Proterozoic ( ) is the third of the four geologic eons of Earth's history, spanning the time interval from 2500 to 538.8 Mya, and is the longest eon of Earth's geologic time scale. It is preceded by the Archean and followed by the Phanerozo ...

. Lithologically, the Freda Sandstone is a lithic, red-brown, cyclic sequence of sandstones, mudstones and shales (conglomerates are rare).

References

* * Geologic formations of Michigan Sandstone formations of the United States Mudstone formations of the United States Shale formations of the United States {{Michigan-geologic-formation-stub