St. Joe Formation

{{Short description|Geologic formation or member in northern Arkansas}}

{{Use dmy dates|date=February 2025}}

{{Infobox rockunit

| name = St. Joe Limestone Member

| image =

| caption =

| type = Member

| age = Mississippian

| prilithology = Limestone

| otherlithology = Chert

| namedfor = St. Joe, Searcy County, Arkansas

| namedby = T.C. Hopkins{{cite journal|last1=Hopkins|first1=T.C.|title=Marbles and other limestones|journal=Annual Report of the Geological Survey of Arkansas for 1890|date=1893|volume=4|pages=10, 91, 150, 209–211, 244, 249, 253–349, 383, pl. 3}}

| region = Arkansas, Missouri, Oklahoma

| country = United States

| coordinates =

| unitof = Boone Formation

| subunits =

| underlies =

| overlies = Chattanooga Shale

| thickness = up to 100 ft.

| extent =

| area =

| map =

| map_caption =

}}

The St. Joe Formation or St. Joe Limestone Member is a geologic formation or member in northern Arkansas, southern Missouri and northeastern Oklahoma. It preserves fossils of the Mississippian subperiod including crinoids, brachiopods, bryozoa, conodonts, blastoids, ostracods and rugose coral.[http://www.geology.ar.gov/geology/ozark_mississippian.htm St. Joe Limestone]