Formation · Devonian
Ohio Shale
Late Devonian unit, Ohio · Kentucky
The Ohio Shale is the Late Devonian black shale of northern and central Ohio whose Cleveland Member yielded the armoured placoderm Dunkleosteus and the shark Cladoselache to the Cleveland Museum of Natural History. For collectors it means the huge round Huron Shale concretions, Callixylon wood and occasional fish plates from stream beds; the vertebrate sites are protected park land. Dunkleosteus material offered for sale deserves close scrutiny of provenance.
| Country | United States |
|---|---|
| Region | Ohio, Kentucky |
| Age | Famennian, Late Devonian |
| Age range | ~372–359 Ma |
| Macrostrat rank | Fm· Macrostrat |
| Macrostrat age | 384–353 Ma· Macrostrat |
| Lithology | shale, siltstone· Macrostrat |
| Environment | inferred marine, marine· Macrostrat |
| Macrostrat columns | 7 column(s) sampled from 8 unit(s)· Macrostrat |
| Members (Macrostrat) | Chagrin, Cleveland· Macrostrat |
| PBDB collections | 39 collections, 166 occurrences· Paleobiology Database |
Collecting and legality
Cleveland Shale exposures in the Rocky River and Big Creek valleys are Cleveland Metroparks land where collecting is prohibited; the Cleveland Museum of Natural History excavates under permit. Large concretions in Delaware and Franklin counties come from private land and quarries.
Lithology and setting
Black, organic-rich shale with giant carbonate concretions (up to several metres), deposited in an anoxic Late Devonian sea.
Commonly recorded taxa (PBDB)
Genera most often recorded from this unit in the Paleobiology Database (first 200 occurrences): Entactinosphaera (33), Foerstia (23), Stigmosphaerostylus (21), Tetrentactinia (18), Polyentactinia (8), Ceratoikiscum (6), Haplentactinia (6), Trilonche (6), Ceratoikiscump (5), Palaeoscenidium (5), Cyrtentactinia (4), Stethacanthus (4), Entactinosphaerap (3), Stenosteus (3), Tegeolepis (3).
Source: Paleobiology Database
Elsewhere
- Macrostrat: 4174
- macrostratConcept: 3086
- PBDB: strata:Ohio Shale
- Wikidata: Q18158146
- Macrostrat stratigraphic name
- PBDB occurrences for this unit
- Wikipedia: Ohio Shale
- Mindat: Ohio Shale
Cite this article
Stratum Study. "Ohio Shale" (Formation). Stratum Study pack 2026.09, as of 2026-09-19. https://stratum.black/study/formations/ohio-shale. Accessed 2026-09-20.
@misc{stratum-ohio-shale,
title = {Ohio Shale},
author = {{Stratum Study}},
howpublished = {\url{https://stratum.black/study/formations/ohio-shale}},
year = {2026},
note = {Formation article, Stratum Study pack 2026.09, as of 2026-09-19; sources: stratum, macrostrat, pbdb, wikidata, commons. Accessed 2026-09-20.}
} Citations carry the pack version and the article's as-of date so they resolve to the same text later. The facts themselves belong to the sources listed below; cite those for the science.