Trimmers Rock Formation

Olive-gray siltstone and shale, characterized by graded bedding; marine fossils; some very fine grained sandstone in northeast; black shale of Harrell Formation at base in Susquehanna Valley.
State Pennsylvania
Name Trimmers Rock Formation
Geologic age Devonian
Lithologic constituents
Major
Sedimentary > Clastic > Siltstone (Bed)Olive-gray siltstone and shale, characterized by graded bedding; marine fossils
Sedimentary > Clastic > Mudstone > Shale (Bed)Olive-gray siltstone and shale, characterized by graded bedding; marine fossils
Minor
Sedimentary > Clastic > Mudstone > Shale > Black-shale (Bed)black shale of Harrell Formation at base in Susquehanna Valley.
Sedimentary > Clastic > Sandstone (Bed)some very fine grained sandstone in northeast
References

Berg, T.M., Edmunds, W.E., Geyer, A.R., and others, compilers, 1980, Geologic map of Pennsylvania: Pennsylvania Geological Survey, 4th ser., Map 1, 2nd ed., 3 sheets, scale 1:250,000.

Pennsylvania Bureau of Topographic and Geologic Survey, Department of Conservation and Natural Resources, Miles, C.E., and Whitfield, T.G., compilers, 2001, Bedrock Geology of Pennsylvania, edition: 1.0, digital map, scale 1:250,000.

NGMDB product
Counties Carbon - Columbia - Dauphin - Juniata - Lebanon - Luzerne - Lycoming - Mifflin - Monroe - Montour - Northumberland - Perry - Pike - Schuylkill - Snyder - Union