Dry Dredgers Field Trip
To a Northern Kentucky Road Cut
Southgate Member, Kope Formation
October 23, 2004
Page 3: Crinoids Found
Most of the crinoid specimens found that day were only the
long stems, preserved on the surface of rocks.
Now this next picture shows something, both rare and
interesting, that a Dry Dredgers member has found. It's a trace fossil of a
crinoid! The trace appears as evenly spaced ridges on the rock surface. They
were made by a crinoid stem rolling across the ocean floor. I have superimposed
a crinoid stem to the right, in the correct orientation to show you how the stem
would have rolled to make this ichnofossil.
However, most of the crinoid stems in the rocks were
individual columnals. In fact, many of the rocks were made almost entirely of
crinoid pieces, as the picture below illustrates.
Another type of crinoid that was found, is the very large
and unusual Anomalocrinus incurvus.
We typically only find the holdfasts,
which we call "volcanos" for reasons obvious in the picture below.
But these Anamolocrinus holdfasts are more
interesting than normal, because they are found attached to BOTH SIDES of this
calcarious shale nodule! This was a cobble
stone on the ocean floor that, regardless of the comparatively deep
water of the Kope, rolled over in currents and storms, killing the crinoids
growing on it and making a new home for more crinoids (only to later meet the
same fate). The picture below shows that bottom side of the nodule above, and
you can see a holdfast, at left, on that side.
Next Page: Burrows Found That Day
T A B L E OF C O N T E N T S
Page 1: Introduction (collecting pics)
Fossils Found That Day:
Page 2: Crinoids Part 1
Page 3: Crinoids Part 2
Page 4: Burrows
Page 5: Graptolites
Page 6: Trilobites
Page 7: Cephalopods
Page 8: Other Molluscs
Page 9: Brachiopods and Bryozoans
Pics From Our Trip To This Site in 2002
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