The Bigfork Chert is a Middle to 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 the town of Big Fork in Polk 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. The Bigfork Chert is known to produce planerite, turquoise, variscite, and wavellite minerals.
Paleofauna Graptolites Climacograptus C. antiquus Dicellograptus D. divaricatus Diplograptus D. trifidus D. vulgatus Glyptograptus Lasiograptus L. flaccidus Mesograptus M. perexcavatus Orthograptus O. quadrimucronatus
See also
List of fossiliferous stratigraphic units in Arkansas Paleontology in Arkansas
References