Plattin Limestone

{{Short description|Geologic formation in the United States}}

{{Infobox rockunit

| name = Plattin Limestone

| image =

| caption =

| type = Formation

| age = Ordovician

| period = Ordovician

| prilithology = Limestone

| otherlithology =

| namedfor = Plattin Creek, Jefferson County, Missouri

| namedby = Edward Oscar Ulrich{{cite journal|last1=Buckley|first1=E.R.|last2=Buehler|first2=H.A.|title=The quarrying industry of Missouri|journal=Missouri Bureau of Geology and Mines |series=2nd Series|date=1904|volume=2|pages=11, 280}}

| region = Arkansas, Illinois, Missouri

| country = United States

| coordinates =

| unitof = Black River Group

| subunits =

| underlies = Kimmswick Limestone, Kope Formation, Lexington Limestone, and Trenton Limestone

| overlies = Joachim Dolomite and Pecatonica Formation

| thickness = up to 250 feet in Arkansas{{cite journal|last1=McFarland|first1=John David|title=Stratigraphic summary of Arkansas|journal=Arkansas Geological Commission Information Circular|date=2004|orig-year=1998|volume=36|page=6|url=http://geology.ar.gov/pdf/IC-36_v.pdf|access-date=2018-01-11|archive-url=https://web.archive.org/web/20161221195953/http://www.geology.ar.gov/pdf/IC-36_v.pdf|archive-date=2016-12-21|url-status=dead}}

| extent =

| area =

| map =

| map_caption =

}}

The Plattin Limestone is a Middle Ordovician geologic formation in Arkansas, Illinois, and Missouri. The name was first introduced in 1904 by Edward Oscar Ulrich in his study of the geology of Missouri. A type locality was designated at the mouth of the Plattin Creek in Jefferson County, Missouri, however a stratotype was not assigned. As of 2017, a reference section has not been designated. The name was introduced into Arkansas in 1927, replacing part of the, now abandoned, Izard Limestone.{{cite book|last1=Branner|first1=G.C.|title=Outlines of Arkansas' mineral resources|publisher=Bureau of Mines, Manufactures and Agriculture and State Geological Survey|date=1927}}