Harrell Shale
{{Short description|Mapped bedrock in the United States}}
{{Infobox rockunit
| name = Harrell Shale Group
| image =
| caption =
| type = Group
| age = Frasnian
| period = Middle Devonian-Late Devonian
| prilithology = shale, sandstone
| otherlithology =
| namedfor =
| namedby = Charles Butts, 1918Butts, Charles, 1918, [https://archive.org/details/americanjourna4461918newh/page/522/mode/2up Geologic section of Blair and Huntingdon Counties], central Pennsylvania: American Journal of Science, 4th series, v. 46, p. 523-537.
| region = Appalachian Mountains
| country = United States
| coordinates =
| unitof =
| subunits = Burket Shalede Witt, Wallace, Jr., Roen, J.B., and Wallace, L.G., 1993, Stratigraphy of Devonian black shales and associated rocks in the Appalachian basin, IN Roen, J.B., and Kepferle, R.C., eds., Petroleum geology of the Devonian and Mississippian black shale of eastern North America: U.S. Geological Survey Bulletin, 1909-B, p. B1-B57.
| underlies = Brallier Formation, Sonyea Formation, Trimmers Rock Formation
| overlies = Mahantango Formation, Millboro Shale, and Tully Limestone
| thickness =
| extent =
| area =
| map =
| map_caption =
}}
The Devonian Harrell Formation is a mapped bedrock unit in Pennsylvania, Maryland, West Virginia, and Virginia.
Description
=Fossils=
Hasson and Dennison reported the following fossils from several outcrops of the Harrell:Hasson, Kenneth O., and Dennison, John M., 1978, STRATIGRAPHY OF THE DEVONIAN HARRELL AND MILLBORO SHALES IN PARTS OF PENNSYLVANIA, MARYLAND, WEST VIRGINIA, AND VIRGINIA, Project Final Report for Energy Research and Development Administration Contract #EY-77-C-21-8153, May 1978 [https://edx.netl.doe.gov/dataset/stratigraphy-of-the-devonian-harrell-and-millboro-shales-in-parts-of-pennsylvania-maryland-west-v]
- Bivalvia: Buchiola livonae (?), B. retrostriata, Paracardium doris, Pterochaenia fragilis, Lunlulicardium (?)
- Cephalopoda: Bactrites aciculum, Probeloceras lutheri
- Cricoconarida (class of Mollusca): Styliolina fissurella
=Notable Exposures=
Type locality is at Horrell Station, Blair County, Pennsylvania ({{coord|40|27|N|78|17|W}}). In 1918, when Butts described and named the type section, the USGS topo map spelled the location "Harrell", {{cite web |url=https://maps.lib.utexas.edu/maps/topo/pennsylvania/txu-pclmaps-topo-pa-hollidaysburg-1902.jpg|title="Topography: Hollidaysburg Quadrangle" |publisher=Department of the Interior|date=1920}} but the local spelling was "Horrell".{{cite news |url=https://www.newspapers.com/article/the-pittsburgh-post-another-mcabee-plant/23065109/ |title=Another McAbee plant explosion |newspaper=The Pittsburgh Post |date=18 August 1904 |page=5 }}{{cite web |url=https://www.west2k.com/pastations/blair.shtml |title=Blair County Pennsylvania Railroad Stations }}
Age
Relative age dating places the Harrell in the late Devonian.
References
{{Reflist|2}}
{{Stratigraphic column of West Virginia}}
{{Clear}}
Category:Devonian System of North America
Category:Shale formations of the United States
Category:Devonian geology of Pennsylvania
Category:Devonian Pennsylvania
Category:Devonian geology of Virginia