Marl Slate Formation

{{Short description|Geologial formation in England}}

{{Use dmy dates|date=April 2022}}

{{Infobox rockunit

| name = Marl Slate Formation

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| type = Formation

| age = {{fossilrange|Lopingian}}

| period = Lopingian

| prilithology =Dolomite

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| region = England

| country = United Kingdom

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| underlies =Raisby Formation, Cadeby Formation

| overlies =Yellow Sands Formation or unconformity with Carboniferous Coal Measures

| thickness =To 5.48 metres

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The Marl Slate Formation is a geological formation in England. Despite its name, it is mostly dolomite rock.{{cite web | url=https://www.bgs.ac.uk/lexicon/lexicon.cfm?pub=MLSL | title=Marl Slate Formation | publisher=British Geological Survey | work=BGS Lexicon of Named Rock Units | accessdate=12 October 2019}} The Marl Slate Formation was formed about 273 to 259 million years ago, during the Guadalupian and Lopingian epochs of the late Permian period of the Earth's geological history. This formation is part of the Zechstein Group of rocks, and is equivalent to the Kupferschiefer of Germany. The Marl Slate Formation contains fossils including the conodont Mesogondolella britannica and the dorypterid fishes Dorypterus and Lekanichthys,{{cite web | url=https://paleobiodb.org/classic/displayCollResults?collection_no=125324 | title=Railway-cutting at Ferryhill (Permian of the United Kingdom) | publisher=Fossilworks | work=Gateway to the Paleobiology Database | access-date=17 December 2021 }} as well as the gliding reptile Weigeltisaurus{{Cite journal|last1=Pritchard|first1=Adam C.|last2=Sues|first2=Hans-Dieter|last3=Scott|first3=Diane|last4=Reisz|first4=Robert R.|date=2021-05-20|title=Osteology, relationships and functional morphology of Weigeltisaurus jaekeli (Diapsida, Weigeltisauridae) based on a complete skeleton from the Upper Permian Kupferschiefer of Germany|journal=PeerJ|language=en|volume=9|pages=e11413|doi=10.7717/peerj.11413|pmid=34055483|issn=2167-8359|pmc=8141288 |doi-access=free }} and terrestrial reptile Protorosaurus{{Cite journal|last1=Evans|first1=S. E.|last2=King|first2=M. S.|date=May 1993|title=A new specimen of Protorosaurus (Reptilia: Diapsida) from the Marl Slate (late Permian) of Britain|url=http://pygs.lyellcollection.org/lookup/doi/10.1144/pygs.49.3.229|journal=Proceedings of the Yorkshire Geological Society|language=en|volume=49|issue=3|pages=229–234|doi=10.1144/pygs.49.3.229|issn=0044-0604|url-access=subscription}} The Marl Slate Formation outcrops in County Durham and Yorkshire in north-east England.