It is used as a construction material, manufacture of quicklime, and manganese deposits are mined as well.
[4] The St Clair is designated as a member of the Bainbridge Group in the State of Indiana.
[5] In Illinois, Missouri, Arkansas and Oklahoma it is part of the Hunton Megagroup.
The St. Clair is the Basal member of the Niagaran Series, making it part of the Tippecanoe sequence.
Beds of pink crinoid remains are also found with in this unit, mostly toward the base.