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Callan Bentley's Snapshots

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  1. Pencil cleavage

    Snapshot Title: Pencil cleavage
    Taken by: Callan Bentley

    Image: Outcrop at the intersection of Fort Valley Road and Ramsey Road, Fort Valley, Virginia
    Image Owner: Callan Bentley



    Description:

    Shale/slate splitting equally well along bedding and cleavage, dividing the rock up into rods.



  2. Bedding traces

    Snapshot Title: Bedding traces
    Taken by: Callan Bentley

    Image: Outcrop at the intersection of Fort Valley Road and Ramsey Road, Fort Valley, Virginia
    Image Owner: Callan Bentley



    Description:

    Bedding here strikes southwest and dips shallowly to the northwest.



  3. Scale pencil

    Snapshot Title: Scale pencil
    Taken by: Callan Bentley

    Image: Outcrop at the intersection of Fort Valley Road and Ramsey Road, Fort Valley, Virginia
    Image Owner: Callan Bentley



    Description:

    Mechanical pencil with centimeters marked on the side.



  4. Scale

    Snapshot Title: Scale
    Taken by: Callan Bentley

    Image: Outcrop at the intersection of Fort Valley Road and Ramsey Road, Fort Valley, Virginia
    Image Owner: Callan Bentley



    Description:

    The official scale bar of the Virginia Department of Geology and Mineral Resources. Inchest at top, centimeters at the bottom.



  5. Sense of scale

    Snapshot Title: Sense of scale
    Taken by: Callan Bentley

    Image: Martinsburg Formation, Millner Road and Bethel Road, Shenandoah County, Virginia
    Image Owner: Callan Bentley



    Description:

    Mechanical pencil with centimeters marked along the side.



  6. Sense of scale

    Snapshot Title: Sense of scale
    Taken by: Callan Bentley

    Image: Martinsburg Formation, Millner Road (near Deer Rapids Road), Shenandoah County, Virginia
    Image Owner: Callan Bentley



    Description:

    Pencil with cm demarcations on the side.



  7. Nice little antiform.

    Snapshot Title: Nice little antiform.
    Taken by: Callan Bentley

    Image: Folds and Faults in Foreknobs, Bergton Va
    Image Owner: Alan Pitts



    Description:

    Are these folds all associated with the overriding fault?



  8. Nucleus

    Snapshot Title: Nucleus
    Taken by: Callan Bentley

    Image: Ooids
    Image Owner: Robin Rohrback



    Description:

    A dark nucleus can be seen at the center of this broken ooid. Layers of CaCO3 wrap around it.



  9. Great White Ooid

    Snapshot Title: Great White Ooid
    Taken by: Callan Bentley

    Image: Ooids
    Image Owner: Robin Rohrback



    Description:

    Why's this one so sparkling white?



  10. Cracked eggshell

    Snapshot Title: Cracked eggshell
    Taken by: Callan Bentley

    Image: Ooids
    Image Owner: Robin Rohrback



    Description:

    This ooid has broken open, revealing its interior concentric layering.



  11. Fault

    Snapshot Title: Fault
    Taken by: Callan Bentley

    Image: The Clydesdale Fault, D.C.
    Image Owner: Callan Bentley



    Description:

    The fault is about here, dipping from upper right diagonally toward the lower left.



  12.  Beech tree roots

    Snapshot Title: Beech tree roots
    Taken by: Callan Bentley

    Image: The Clydesdale Fault, D.C.
    Image Owner: Callan Bentley



    Description:

    Twisting through the saprolite.



  13. Hook

    Snapshot Title: Hook
    Taken by: Callan Bentley

    Image: The Clydesdale Fault, D.C.
    Image Owner: Callan Bentley



    Description:

    Did an earlier explanatory sign hang here?



  14. Weathering of urbanite

    Snapshot Title: Weathering of urbanite
    Taken by: Callan Bentley

    Image: The Clydesdale Fault, D.C.
    Image Owner: Callan Bentley



    Description:

    That's what concrete looks like if you leave it in DC humidity for 85 years.



  15. Sense of scale

    Snapshot Title: Sense of scale
    Taken by: Callan Bentley

    Image: The Clydesdale Fault, D.C.
    Image Owner: Callan Bentley



    Description:

    Pencil with centimeter markings on the side.



  16. Skolithos

    Snapshot Title: Skolithos
    Taken by: Callan Bentley

    Image: The Clydesdale Fault, D.C.
    Image Owner: Callan Bentley



    Description:

    trace fossils in this cobble of Antietam Formation.



  17. River gravel deposits

    Snapshot Title: River gravel deposits
    Taken by: Callan Bentley

    Image: The Clydesdale Fault, D.C.
    Image Owner: Callan Bentley



    Description:

    How old? Maybe as much as Cretaceous, maybe much younger.



  18. Metagraywacke schist --> saprolite

    Snapshot Title: Metagraywacke schist --> saprolite
    Taken by: Callan Bentley

    Image: The Clydesdale Fault, D.C.
    Image Owner: Callan Bentley



    Description:

    Ancient seafloor sediments transformed during the first phase of Appalachian mountain-building, then weathered to clay.



  19. Lichen

    Snapshot Title: Lichen
    Taken by: Callan Bentley

    Image: Indiana limestone at the Duke Ellington Bridge, D.C.
    Image Owner: Callan Bentley



    Description:

    .



  20. Rugose coral

    Snapshot Title: Rugose coral
    Taken by: Callan Bentley

    Image: Indiana limestone at the Duke Ellington Bridge, D.C.
    Image Owner: Callan Bentley



    Description:

    Cross-sectioned laterally.



  21. Trace

    Snapshot Title: Trace
    Taken by: Callan Bentley

    Image: Indiana limestone at the Duke Ellington Bridge, D.C.
    Image Owner: Callan Bentley



    Description:

    The sign left a footprint and moved about 20 cm to the left...?



  22. Namesake

    Snapshot Title: Namesake
    Taken by: Callan Bentley

    Image: Indiana limestone at the Duke Ellington Bridge, D.C.
    Image Owner: Callan Bentley



    Description:

    A great jazz musician



  23. Flint cobble

    Snapshot Title: Flint cobble
    Taken by: Callan Bentley

    Image: Gravel deposits on Adams Mill Road NW, DC
    Image Owner: Callan Bentley



    Description:

    Derived from one of the limestones of the Shenandoah Valley's Cambro-Ordovician series?



  24. Coarse sandstone

    Snapshot Title: Coarse sandstone
    Taken by: Callan Bentley

    Image: Gravel deposits on Adams Mill Road NW, DC
    Image Owner: Callan Bentley



    Description:

    .



  25. Rugose coral in cross-section

    Snapshot Title: Rugose coral in cross-section
    Taken by: Callan Bentley

    Image: Indiana limestone at the Duke Ellington Bridge, D.C.
    Image Owner: Callan Bentley



    Description:

    Radial septae obvious even though it's a bit blurry.



  26. Skolithos trace fossil

    Snapshot Title: Skolithos trace fossil
    Taken by: Callan Bentley

    Image: Gravel deposits on Adams Mill Road NW, DC
    Image Owner: Callan Bentley



    Description:

    I ground-truthed this one. It's for real. A piece of the Antietam Formation.



  27. Beer can

    Snapshot Title: Beer can
    Taken by: Callan Bentley

    Image: Gravel deposits on Adams Mill Road NW, DC
    Image Owner: Callan Bentley



    Description:

    Guess what people use this patch of woods for?



  28. Visine bottle

    Snapshot Title: Visine bottle
    Taken by: Callan Bentley

    Image: Gravel deposits on Adams Mill Road NW, DC
    Image Owner: Callan Bentley



    Description:

    Guess what people use this patch of woods for?



  29. Sense of scale II

    Snapshot Title: Sense of scale II
    Taken by: Callan Bentley

    Image: Gravel deposits on Adams Mill Road NW, DC
    Image Owner: Callan Bentley



    Description:

    Pencil, with centimeters marked along the side.



  30. Sense of scale

    Snapshot Title: Sense of scale
    Taken by: Callan Bentley

    Image: Gravel deposits on Adams Mill Road NW, DC
    Image Owner: Callan Bentley



    Description:

    Pencil, with centimeters marked along the side.



  31. Explanation

    Snapshot Title: Explanation
    Taken by: Callan Bentley

    Image: The Clydesdale Fault, D.C.
    Image Owner: Callan Bentley



    Description:

    This diagram shows the rock units offset along this fault in cartoon form.



  32. Contact

    Snapshot Title: Contact
    Taken by: Callan Bentley

    Image: Indiana limestone at the Duke Ellington Bridge, D.C.
    Image Owner: Callan Bentley



    Description:

    between weathered and washed limestone



  33. Bioturbation

    Snapshot Title: Bioturbation
    Taken by: Callan Bentley

    Image: Indiana limestone at the Duke Ellington Bridge, D.C.
    Image Owner: Callan Bentley



    Description:

    in skeletal limestone



  34. Sense of scale

    Snapshot Title: Sense of scale
    Taken by: Callan Bentley

    Image: Indiana limestone at the Duke Ellington Bridge, D.C.
    Image Owner: Callan Bentley



    Description:

    Pencil, with centimeters marked along the side.



  35. Glad for his windbreaker

    Snapshot Title: Glad for his windbreaker
    Taken by: Callan Bentley

    Image: Smithsonian Castle, Washington, DC
    Image Owner: Callan Bentley



    Description:

    It was blustery out that day.



  36. Xenolith

    Snapshot Title: Xenolith
    Taken by: Callan Bentley

    Image: Granite slab, Haupt Gardens, Smithsonian Instituion, Washington, DC
    Image Owner: Callan Bentley



    Description:

    mantled by K-spar



  37. American flag

    Snapshot Title: American flag
    Taken by: Callan Bentley

    Image: Smithsonian Castle, Washington, DC
    Image Owner: Callan Bentley



    Description:

    Blowing in the wind



  38. Cleavage

    Snapshot Title: Cleavage
    Taken by: Callan Bentley

    Image: Granite slab, Haupt Gardens, Smithsonian Instituion, Washington, DC
    Image Owner: Callan Bentley



    Description:

    on a potassium feldspar crystal - catching the sunlight at just the right angle.



  39. Sense of scale

    Snapshot Title: Sense of scale
    Taken by: Callan Bentley

    Image: Granite slab, Haupt Gardens, Smithsonian Instituion, Washington, DC
    Image Owner: Callan Bentley



    Description:

    cm-demarcated pencil



  40. Porcupine

    Snapshot Title: Porcupine
    Taken by: Callan Bentley

    Image: Monkeypuzzle tree, Haupt Gardens, Smithsonian Castle, Washington, DC
    Image Owner: Callan Bentley



    Description:

    Pretty much: you wouldn't want to rub the tip of this branch against your cheek.



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