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When a dig begins, there
is always the promise that it just might be a
spectacular skeleton. More often than not
it isn't.
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After a moderate amount of
overburden is removed, a serious effort is made
to try to determine which way to dig.
Experience and a great deal of luck guide the
collector at this point
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Once the collector gets a
fix on which way to dig, about one square yard
of overlying rock is removed at a time.
More than that could mean a lot of wasted effort
going in the wrong direction.
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A very tired Mike Triebold
surveys the dig site after a week of dawn to
dusk days with no end in sight.
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One week later, the
perimeter of the entire skeleton has been
located, and the work of preparing slabs for
jacketing and transport begins.
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A second view of the site
once the entire perimeter has been
located.
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Closeup of one of the more
interesting and revealing parts of the skeleton,
the business end of the bad boy himself, the
left lower jaw with front teeth measuring 3
inches long.
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Care must be taken to
prevent weather damage while the dig is in
progress. The skeleton has been protected
from the elements by the overlying rock for
millions of years, but once exposed, the bones
deteriorate very rapidly unless well
protected.
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Ptychodus mortoni
was a clam-crushing shark that lived
alongside Xiphactinus in these ancient
seas.
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Jon Wagar fixing the
position of the digsite for the camera using the
high-tech finger-on-the-horizon
method.
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A just slightly closer
photo of the environment of the dig.
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Determining the
stratigraphic position or relative age of any
discovery in the Niobrara chalk is now
fairly easy since the bentonite layers were
mapped by Hattin.
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Other fossils with limited
stratigraphic ranges also help secure the date
of the find.
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This overlay shows the
approximate position of the fossil in
situ.
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This is the same photo
without the overlay. You can see that
channels have been started around sections of
the skeleton.
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The slab in the center of
the photo is almost ready to jacket. All
precautions have been taken to insure that it
will be safely removed and
transported.
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Final steps in the process
include jacketing in plaster and burlap,
releasing from the underlying rock and tipping
over for transport. Once in the lab, the
real work
begins!
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