earth science

Pottsville Formation

Pottsville Formation is a earth science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Pottsville Formation rather than just read about it. In short: The Pennsylvanian Pottsville Formation is a mapped bedrock unit in Pennsylvania, western Maryland, West Virginia, Ohio, and Alabama. It is a major ridge-former in the Ridge-and-Valley Appalachians of the eastern United States.

Key takeaways

Pottsville Formation belongs to earth science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Pottsville Formation to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Pottsville Formation from memory before moving on to harder problems.

Reference excerpt

The Pennsylvanian Pottsville Formation is a mapped bedrock unit in Pennsylvania, western Maryland, West Virginia, Ohio, and Alabama. It is a major ridge-former in the Ridge-and-Valley Appalachians of the eastern United States. The Pottsville Formation is conspicuous at many sites along the Allegheny Front, the eastern escarpment of the Allegheny or Appalachian Plateau.

Description The Pottsville Formation consists of a gray conglomerate, fine to coarse grained sandstone, and is known to contain limestone, siltstone and shale, as well as anthracite and bituminous coal. It is considered a classic orogenic molasse. The formation was first described from a railroad cut south of Pottsville, Pennsylvania.

Nomenclature and stratigraphy The relationship to the term "Pottsville" and actual lithologic units is complex. Most fundamentally, the unit may be considered a formation or a group. As a formation, the Pottsville may encompass the following members depending on the state in which it occurs: Alton Coal Member, Anthony Shale Member, Bear Run Member, Bedford Clay Bed, Boggs Member, Boyles Sandstone Member, Bremen Sandstone Member, Brookville Clay Member, Camp Branch Sandstone Member, Campbell Ledge Shale Member, Chestnut Sandstone Member, Connoquenessing Sandstone Member, Dundee Sandstone Member, Flint Ridge Clay Bed or Flint Ridge Shale Member, Harrison Member, Homewood Sandstone Member, Huckleberry Clay Bed, Kanawha Member, Lick Creek Sandstone Member, Lowellville Limestone Member, Lower Mercer Limestone Member, Massillon Sandstone Member, McArthur Member, Mercer Member, Middle Mercer Shale Member, Mount Savage Clay Bed, Olean Conglomerate Member of Olean Sandstone Member, Pine Sandstone Member, Poverty Run Member, Razburg Sandstone Member, Rocky Ridge Sandstone Member, Schuylkill Member, Sciotoville Clay Member, Shades Sandstone Member, Sharon Coal Bed, Sharon Member, Sharp Mountain Member, Straight Ridge Sandstone Member, Straven Conglomerate Member, Tionesta Clay Bed, Tumbling Run Member, Upper Mercer Limestone Member or Upper Mercer Bed, Vandusen Shale Member, Wolf Ridge Sandstone Member. As a group, the Pottsville may encompass the following formations depending on the state in which it occurs: Connoquenessing Formation, Curwensville Formation, Elliott Park Formation, Gurnee Formation, Hance Formation, Homewood Formation or Homewood Sandstone, Mercer Formation, New River Formation, Olean Conglomerate or Olean Formation, Pocahontas Formation, Schuylkill Formation, Sharon Formation or Sharon Sandstone, Sharp Mountain Formation, Tumbling Run Formation. The Pottsville was previously mapped in the Illinois basin as well at the Formation level, but was renamed the Tradewater Formation in 1997.

Fossils A 1.3-m interval at the base of the Pottsville in the Broad Top basin in Pennsylvania contains both marine invertebrates and plant fossils of middle Morrowan age.

Age Relative age dating of the Pottsville places it in the Early to Middle Pennsylvanian period.

Notable exposures

Pennsylvania:

Bilger's Rocks Worlds End State Park Maryland:

Dans Rock, on Dans Mountain West Virginia:

Bear Rocks Preserve, Dolly Sods Blackwater Falls and the Blackwater Canyon Canaan Valley (surrounding mountains) Cheat River Gorge Spruce Knob Ohio:

Thompson Ledges in Thompson Township, Geauga County, Ohio

See also Carboniferous Ohio Carboniferous Pennsylvania Carboniferous West Virginia Pennsylvanian North America Upper Mercer flint

References

Illustrations

Worked examples

Example 1 — a first encounter with Pottsville Formation

Start with the simplest possible case. Write down what Pottsville Formation claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In earth science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Pottsville Formation before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Pottsville Formation ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Pottsville Formation

In research: Pottsville Formation appears in earth science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Pottsville Formation in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Pottsville Formation is common in secondary-school and first-year university syllabi. It links to neighbouring topics Carboniferous Ohio, Carboniferous West Virginia, Carboniferous geology of Pennsylvania, so understanding it makes those chapters shorter.
In everyday life: Look for Pottsville Formation outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Pottsville Formation in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Pottsville Formation means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Pottsville Formation out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Pottsville Formation in simple terms?

Why does Pottsville Formation matter?

Because it connects several earth science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Pottsville Formation?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Pottsville Formation.