View source for Harpers Formation

{{Infobox rockunit
| name           = Harpers Formation
| image          = File:Bulletin 799 Plate 8A Harpers Schist.jpg
| caption        = Harpers Schist. Shows older folded schistosity parallel to bedding cut by younger cleavage inclined to bedding.
| type           = [[Metamorphic rock|Metamorphic]]
| age            = [[Cambrian]]
| period         = Cambrian
| prilithology   = [[Schist]]
| otherlithology = [[Phyllite]], [[shale]]
| namedfor       = [[Harpers Ferry, West Virginia]]
| namedby        = Arthur Keith (1894)<ref>Arthur Keith, 1894. Harpers Ferry folio, Virginia, Maryland, West Virginia. [[United States Geological Survey]] Geologic atlas of the U.S. Folio 10. Field edition. Washington D.C., engraved and printed by the US Geological Survey.  5p., 5 maps. folio.</ref>
| region         = [[Appalachia]], [[Mid-Atlantic United States]], and [[Southeastern United States]]
| country        = [[United States]]
| coordinates    =
| unitof         = [[Chilhowee Group]]
| subunits       = Snowden Member (VA), Montalto Quartzite Member (PA)
| underlies      = [[Antietam Formation]]
| overlies       = [[Weverton Formation]]
| thickness      =
| extent         = [[Maryland]], [[Pennsylvania]], [[Virginia]],<ref>[http://hdl.handle.net/10919/19078 Paleozoic Sedimentary Successions of the Virginia Valley & Ridge and Plateau]</ref> [[West Virginia]]
| area           =
| map            =
| map_caption    =
}}
[[File:Bulletin 799 Plate 2A Harpers Schist photomicrograph.jpg|thumb|upright=1.2|Photomicrograph of Harpers Schist]]
The '''Harpers Formation''' is a [[Formation (geology)|geologic formation]] in [[Maryland]], [[Pennsylvania]], [[Virginia]], and [[West Virginia]], consisting of [[schist]], [[phyllite]], and [[shale]]. It dates back to the early [[Cambrian]] [[Period (geology)|period]].  It is considered part of the [[Chilhowee Group]].

==Notable exposures==
The type section is in gorges of the [[Potomac River]] and the [[Shenandoah River]] at [[Harpers Ferry, West Virginia]].

The Harpers Formation overlies the [[Ledger Formation]] ([[Dolomite (rock)|dolomite]]) due to a [[thrust fault]] in small roadside quarry (currently overgrown) on Pottery Hill, southwest of [[York, Pennsylvania]].<ref> A. J. Stose and G. W. Stose, 1944.  ''Geology of the Hanover-York district'', [[U. S. Geological Survey]] Professional paper 204.</ref>

==Gallery==
<gallery heights=150px widths=225px mode="nolines">
File:Quartzite (Harpers Formation, Lower Cambrian; Verona, Virginia, USA).jpg|Quartzite sample of Harpers Formation from near [[Verona, Virginia]]
File:Jefferson Rock, Harpers Ferry, WV - area view.jpg|Harpers Shale by [[Jefferson Rock]] in [[Harpers Ferry, West Virginia]]
Harpers Phyllite Pottery Hill outcrop 2022.jpg|Sample of phyllite from the outcrop at Pottery Hill, southwest of [[York, Pennsylvania|York]]
</gallery>

==References==
{{reflist}}

{{Portal|Earth sciences|Paleontology}}

{{Chronostratigraphy of Virginia}}
{{Stratigraphic column of West Virginia}}

[[Category:Cambrian West Virginia]]


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