Jefferson City Formation

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| name = Jefferson City Formation

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| type = Formation

| age = Early Ordovician

| period = Early Ordovician

| prilithology = Dolomite

| otherlithology = Chert, sandstone

| namedfor = Jefferson City, Cole County, Missouri{{cite journal|last1=Winslow|first1=A.|title=Lead and zinc deposits, section 1|journal=Geological Survey of Missouri|date=1894|volume=6|pages=331, 373, 375}}

| namedby = Arthur Winslow

| region = Arkansas, Missouri

| country = United States

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| underlies = Cotter Dolomite

| overlies = Roubidoux Formation[http://www.dnr.mo.gov/geology/geosrv/ogc/docs/RI-073.pdf Thompson, Thomas L., 2001, Lexicon of Stratigraphic Nomenclature in Missouri, Missouri Department of Natural Resources, Division of Geology and Land Survey, Report of Investigation Number 73, p 145]

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The Jefferson City Formation or Jefferson City Dolomite is a geologic formation in the Ozarks of Missouri and Arkansas. The Jefferson City is in part not differentiated from the Cotter Formation of northern Arkansas.{{Cite web |url=http://www.geology.ar.gov/geology/ozark_ordovician.htm |title=Ordovician of the Ozark Plateau |access-date=2014-07-11 |archive-url=https://web.archive.org/web/20140714131645/http://www.geology.ar.gov/geology/ozark_ordovician.htm |archive-date=2014-07-14 |url-status=dead }} It preserves fossils dating back to the Ordovician period.