Английская Википедия:Dunkard Group

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Шаблон:Infobox rockunit The Permian Dunkard Group (Pd) is an area of rock, Early Permian in age, in the south of Ohio, southwestern Pennsylvania, West Virginia and the hilltops of the Georges Creek Basin of Maryland.[1] In Ohio, it is found primarily in Washington County. It is notable for being one of the few areas of Permian sediment east of the Mississippi River. In addition, it is the youngest surface rock in the state of Ohio.

Description

It consists of red and green shale, siltstone, and sandstone, with thin lenticular beds of argillaceous limestone and thin beds of impure coal The base of the layer contains thick-bedded, white conglomeratic sandstone. The layer's thickness is greater than 200 feet in Maryland.[1]

The fossils found in the Dunkard Group are similar to ones found in Texas and Oklahoma of similar age.

Stratigraphy

The Dunkard contains three formation. Starting at the base (oldest) is the Waynesburg Formation, Washington Formation, and Greene Formation. The base is marked by the Waynesburg Coal, with the Monongahela Group below. The Washington Coal is found at the base of the Washington Formation and its base marks the boundary between the lower Waynesburg and the Washington formation above. The top of the Upper Washington Limestone marks the line between the Washington Formation and the upper Greene formation.

Fossil content

Portrait Name
Файл:Dimetrodon grandis 3D Model Reconstruction.png Dimetrodon
Файл:Ctenospondylus2DB2.jpg Ctenospondylus
Файл:Archaeothyris BW.jpg Archaeothyris
Файл:Edaphosaurus-Field Museum.jpg Edaphosaurus
Файл:Eryops1DB.jpg Eryops
Файл:Xenacanth.png Xenacanthus
Файл:Ophiacodon FMNH.jpg Ophiacodon
Файл:Diploceraspis12DB.jpg Diploceraspis
Файл:Protorothyris.jpg Protorothyris
Файл:Diadectes1DB.jpg Diadectes
Файл:Isodectes obtusus.jpg Isodectes
Файл:Brachydectes NT small.jpg Brachydectes
Файл:Phlegethontia.jpg Phlegethontia
Baldwinonus
Sagenodus
Sysciophlebia balteata


References

Шаблон:Reflist

Further reading

Шаблон:Chronostratigraphy of Ohio Шаблон:Chronostratigraphy of Pennsylvania Шаблон:Stratigraphic column of West Virginia