Corals of the St. Louis Limestone in the area of Calhoun County, Illinois and St. Louis County, Missouri

The St. Louis Limestone and its equivalent formations crop out from Alaska south to Sonora and from Arizona east to Virginia. The St. Louis, in most cases, is fossiliferous and contains numerous species of foraminifers, echinoderms, bryozoans, molluscans, brachipods, arthropods and coelenterates. Algal mounds and mats are common. The rugose coral fauna of the Middle Mississippian (Meramecian) St. Louis Limestone of southern Calhoun County, Illinois and northern St. Louis County, Missouri was studied to determine first what corals were present and second the validity of the names assigned to the previously described species. It was found that the binomen for the coral Lithostrotion proliferurn Hall 1858 has long been in error and that this species actually belongs to the genus Koninckophyllum Thomson and Nicholson. After careful study of these corals and specimens of L. proliferum from Kentucky and Koninckophyllum arizellum Crickmay 1955, data were compared and the corals found to be conspecific. The name, Koninckophyllum proliferum (Hall), is therefore proposed for this species. The utility of Koninckophyllum proliferum as an index fossil within the formation in this area was found to be nonexistent due to its broad vertical range. The environment of deposition is postulated as a warm shallow sea with frequent but slight undulations of both sea floor and neighboring landmass to allow for argillaceous sediments to accumulate in thin layers in an otherwise totally limestone sequence --Abstract, page ii