The Franconia Formation 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 ...

in the upper mid-western United States, with outcroppings found in

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, and

Wisconsin Wisconsin () is a state in the upper Midwestern United States. Wisconsin is the 25th-largest state by total area and the 20th-most populous. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake M ...

. It preserves

fossils A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in ...

dating back to the

Cambrian The Cambrian Period ( ; sometimes symbolized C with bar, Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million ...

period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept ...

. It was named the Franconia Formation due to the first published documentation of exposures in vicinity of

Franconia Franconia (german: Franken, ; Franconian dialect: ''Franggn'' ; bar, Frankn) is a region of Germany, characterised by its culture and Franconian dialect (German: ''Fränkisch''). The three administrative regions of Lower, Middle and Upper Fr ...

, Minnesota in the 1897 Ph.D. dissertation by Charles P. Berkley at the University of Minnesota titled Geology of the St. Croix Dalles. The Franconian

stratigraphic stage In chronostratigraphy, a stage is a succession of rock strata laid down in a single age on the geologic timescale, which usually represents millions of years of deposition. A given stage of rock and the corresponding age of time will by conventi ...

was named after this formation. The formation consists of fine-grained dolomitic sandstone with interbedded shaly zones, becoming more dolomitic towards the east and south of its extent.

References

*
USGS National Geologic Map Database Unit Summary for "Franconia"Indiana Geological and Water Survey: Franconia Information at the University of Indiana
Cambrian geology of Wisconsin Cambrian Minnesota Cambrian southern paleotropical deposits {{Wisconsin-geologic-formation-stub

See also

References