Harrell Shale
Mapped bedrock in the United States
The Devonian Harrell Formation is a mapped bedrock unit in Pennsylvania, Maryland, West Virginia, and Virginia.
01Description
The Harrell Formation was first described by Charles Butts in 1918. Hasson and Dennison (1978) state "The Harrell Shale consists of very dark gray, thinly laminated, platy- to sheety-weathering shale underlain in certain areas by the grayish black shale of the Burket Member."
Fossils
Hasson and Dennison reported the following fossils from several outcrops of the Harrell:
- 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 (40°27′N 78°17′W / 40.450°N 78.283°W / 40.450; -78.283). In 1918, when Butts described and named the type section, the USGS topo map spelled the location "Harrell", but the local spelling was "Horrell".
02Age
Relative age dating places the Harrell in the late Devonian.
Sources and credits
This article is adapted from the Wikipedia article “Harrell Shale”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.
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