The Polk Creek Shale is a Late Ordovician geologic formation in the Ouachita Mountains of Arkansas and Oklahoma. First described in 1892, this unit was not named until 1909 by Albert Homer Purdue in his study of the Ouachita Mountains of Arkansas. Purdue assigned Polk Creek in Montgomery County, Arkansas as the type locality, but did not designate a stratotype. As of 2017, a reference section for this unit has yet to be designated.

Paleofauna

Graptolites

Amplexograptus

Climacograptus

C. mississippiensis

C. putillus

C. tridentatus var. maximus

C. ulrichi

Dicellograptus

D. anceps

D. complanatus

D. elegans

D. forehammeri flexuosus

Diplograptus

D. calcaratus

D. calcaratus var. trifidus

D. crassitestus

Glossograptus

G. quadrimucronatus

G. quadrimucronatus var. paucithecatus

Lasiograptus

Mesograptus

Nymphograptus

N. velatus

Orthograptus

O. quadrimucronatus

O. spinigerus

See also

List of fossiliferous stratigraphic units in Arkansas

Paleontology in Arkansas

References

Ordovician geology of Oklahoma

Ordovician Arkansas

Ordovician southern paleotropical deposits

Polk Creek Shale