The Womble Shale is a Middle
Ordovician
The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya.
T ...
geologic formation
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...
in the
Ouachita Mountains
The Ouachita Mountains (), simply referred to as the Ouachitas, are a mountain range in western Arkansas and southeastern Oklahoma. They are formed by a thick succession of highly deformed Paleozoic strata constituting the Ouachita Fold and Thru ...
of
Arkansas
Arkansas ( ) is a landlocked state in the South Central United States. It is bordered by Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, and Texas and Oklahoma to the west. Its name is from the O ...
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, where he named this unit as part of the upper Ouachita Shale and the Stringtown Shale.
In 1918,
U.S. Geological Survey
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and ...
geologist, Hugh Dinsmore Miser, replaced Purdue's nomenclature with the Womble Shale.
[ Miser assigned the town of Womble (now called ]Norman
Norman or Normans may refer to:
Ethnic and cultural identity
* The Normans, a people partly descended from Norse Vikings who settled in the territory of Normandy in France in the 10th and 11th centuries
** People or things connected with the Norm ...
) in Montgomery County, Arkansas as the type locality. As of 2017, a reference section for this unit has yet to be designated.
Paleofauna
Bryozoa
Bryozoa (also known as the Polyzoa, Ectoprocta or commonly as moss animals) are a phylum of simple, aquatic invertebrate animals, nearly all living in sedentary colonies. Typically about long, they have a special feeding structure called a ...
* '' Rhinidictya''
Graptolites
Graptolites are a group of colonial animals, members of the subclass Graptolithina within the class Pterobranchia. These filter-feeding organisms are known chiefly from fossils found from the Middle Cambrian ( Miaolingian, Wuliuan) through th ...
* '' Azygograptus''[
* '' Brygraptus''][
* '']Climacograptus
''Climacograptus'' is an Ordovician to Silurian genus of graptolite
Graptolites are a group of colonial animals, members of the subclass Graptolithina within the class Pterobranchia. These filter-feeding organisms are known chiefly from f ...
''
: ''C. bicornis''[
: ''C. caudatus''][
: ''C. parvus''][
: ''C. pultifer''][
* '' Cryptograptus''
: ''C. insectiformis''][
: ''C. tricornis''][
* '' Desmograptus''][
* '' Dicellograptus''
: ''D. diapason''][
: ''D. divaricatus''][
: ''D. gurleyi''][
: ''D. intorius''][
: ''D. parvangulus''][
: ''D. rectus''][
: ''D. rigidus''][
: ''D. sextans''][
* '' Dicranograptus''
: ''D. arkansasensis''][
: ''D. nicholsoni''][
: ''D. nicholsoni var. diapason''][
: ''D. nicholsoni var. parvangulus''][
: ''D. parvangulus''][
: ''D. ramosus''][
: ''D. spinifer''][
* '' Dictyonema''][
* '' Didymograptus''
: ''D. sagitticaulis''][
: ''D. sagitticaulus var. minimus''][
: ''D. sparsus''][
: ''D. superstes''][
* '' Diplograptus''
: ''D. acutus''][
: ''D. (Glyptograptus) angustifolius''][
: ''D. basilicus''][
: ''D. euglyphus''][
: ''D. incisus''][
: ''D. truncatus abbreviatus''][
* '' Glossograptus''
: ''G. ciliatus''][
: ''G. horridus''][
: ''G. quadrimucronatus var. maximus''][
* '' Glyptograptus''
: ''G. angustifolius''][
: ''G. englyphus''][
* '' Lasiograptus''
: ''L. bimucronatus''][
: ''L. mucronatus''][
* '' Leptograptus''
: ''L. patulosus''][
* '' Mesograptus''][
* '' Nemagraptus''
: ''N. gracilis''][
* '' Orthograptus''][
* '']Phyllograptus
''Phyllograptus'' is a graptolite genus of the order Graptoloidea, in the family Phyllograptidae.
Fossils of this genus have been found in the Early Ordovician (475-473 million years ago), in the sediments of Australia, Bolivia, Canada, Chile, ...
''[
* '' Retiograptus''
: ''R. geinitzianus''][
: ''R. quadrimucronatus cornutus''][
* '' Thamnograptus''
: ''T. capillaris''][
]
See also
* List of fossiliferous stratigraphic units in Arkansas
This article contains a list of fossil-bearing stratigraphic units in the state of Arkansas, U.S.
Sites
See also
* Paleontology in Arkansas
References
*
{{DEFAULTSORT:Fossiliferous stratigraphic units in Arkansas
Arkansas
Stratigraph ...
* Paleontology in Arkansas
References
Ordovician geology of Oklahoma
Ordovician Arkansas
Ordovician southern paleotropical deposits
{{US-geologic-formation-stub