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MAP

Topo

Rock Formations

Measure

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Topo

Ecoregions

Public Lands

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BASEMAPS

Default Weather

Temperature

Smoke

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WEATHER

Keyser and Tonoloway Formations, undivided (PADSkt;19)

Geologic Formation in PA

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Lithology

Limestone

Shale

Geologic Age

Silurian – Devonian (445.3 Ma – 359.3 Ma ago)

Geologic Unit Label

DSkt9

In descending order: Keyser Formation–medium-gray, crystalline to nodular, fossiliferous limestone; upper part laminated and mud-cracked; not present east of Harrisburg; passes into lower Coeymans, Rondout, and Decker Formations in the east. Tonoloway Formation–medium-gray, laminated, mud-cracked limestone containing some medium-dark- or olive-gray shale interbeds; lower part passes into Wills Creek Formation east and south; passes into Bossardville and Poxono Island beds in the east.

— USGS

Taxonomy

Classified As

Geologic Formation