Ada Formation

{{Short description|Geologic formation in Oklahoma}}

{{Infobox rockunit

| name = Ada Formation

| type = Formation

| age = Late Pennsylvanian

| namedfor = Ada, Pontotoc Co, OK

| region = Oklahoma

| country = United States

}}

The Ada Formation is a geologic formation in Oklahoma, within and to west of Ada.{{cite web|title= Fossilworks: Gateway to the Paleobiology Database|author= ((Various Contributors to the Paleobiology Database))|url= https://www.fossilworks.org|access-date= 17 December 2021}} It consist mainly of shale with numerous limestone layers which get thinner and eventually disappear to the south, where they are replaced by fine-grained sandstone. Fossils are rare.{{cite web|website= Mineral Resources On-Line Spatial Data|author= USGS|title= Ada Group or Ada Formation|url= http://mrdata.usgs.gov/geology/state/sgmc-unit.php?unit=OKPAa%3B0|accessdate= 2016-02-18}} Disarticulated remains of Eryops, Diasparactus, and Ophiacodon from the Ada Formation represent the first finds of these genera in Oklahoma.{{cite journal|first1= Richard A.|last1= Kissel|first2= Thomas M.|last2= Lehman|year= 2002|title= Upper Pennsylvanian Tetrapods from the Ada Formation of Seminole County, Oklahoma|journal= Journal of Paleontology|volume= 76|issue= 3|pages= 529–545|jstor= 1307163}}