[2] The Clifty Limestone is a Middle Devonian geologic formation in the Ozark Plateaus of Arkansas.

[3] The name was introduced in 1916 by Albert Homer Purdue and Hugh Dinsmore Miser in their study of northern Arkansas.

They designated a stratotype along the East Fork of Little Clifty Creek in Benton County, Arkansas.

[5] Miser designated a type locality near the old Penters Bluff railroad station in Izard County, Arkansas, however, he did not assign a stratotype.

It was named for the now abandoned town of Bailey's Landing near the village of Grand Eddy, on the Mississippi River.

[6] The Lafferty Limestone is a Middle to Late Silurian geologic formation in the Ozark Plateaus of Arkansas.

[5] The name was introduced in 1921 by Hugh Dinsmore Miser in his study of Arkansas, replacing part of the upper St. Clair Limestone.

[3] Miser designated a type locality at Tate Spring, located 1.25 miles north of the site of the old Penters Bluff railroad station in Izard County, Arkansas, however, he did not assign a stratotype.

It contains fossils of many species of trilobites, brachiopods, crinoids, gastropods among others[8] This formation is found in Illinois, Iowa, Missouri and Wisconsin.

These reefs also make up the Terre Haute Bank on the eastern flank of the Illinois Basin.

The St. Clair is the Basal member of the Niagaran Series, making it part of the Tippecanoe sequence.

[17] In exposures the following fossils have been found; Distacodus obliquicostatus, Pterospathodus amorphognathoides, Kockelella ranuliformis.